An environmentally friendly large-scale preparation method of fluoride nanomaterial, wherein the fluoride is MF 2, REF 3 or compound fluoride; the compound fluoride is one or more than one of AMF 3, AREF 4, A 2 REF 5, A 3 REF 6, ARE 2 F 7, A 2 RE 2 F 8, ARE 3 F 10, ARE 7 F 22, A 5 RE 9 F 32, MREF 5, M 2 REF 7, MRE 2 F 8, MRE 4 F 14 or REOF; M is one or more than one of Be, Mg, Ca, Sr, Ba, Zn, Cd or Mn; RE is one or more than one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, Al, Ga or Bi; A is one or more than one of Li, Na, K, Rb or Cs,wherein the method comprises the following specific preparation steps: step 1: taking oxide, carbonate, basic carbonate or hydroxide containing M and/or RE as raw material; adding volatile acid a to the raw material; or directly taking volatile acid salt containing M and/or RE as raw material; heating to reflux to dissolve the raw material; and converting the raw material into water-soluble salt to obtain a water-soluble salt solution b; filtering precipitates which may exist in the solution; wherein the volatile acid a is one or a mixture of more than one of hydrochloric acid, perchloric acid, hydrobromic acid, nitric acid, formic acid, acetic acid and propionic acid; step 2: conducting a decompression process on the water-soluble salt solution b in step 1 to evaporate excess volatile acid a and water which do not participate in the reaction, wherein evaporation temperature is 50-130°C and relative vacuum is - (0.01-0.09) MPa; then, adding oily organic matter c with high boiling point to continue evaporation under reduced pressure; replacing the volatile acid bound with M and/or RE, wherein evaporation temperature is 80-160°C and vacuum is 1-3000 Pa; converting all the water-soluble salt b into oil-soluble precursor salt to obtain an oil-soluble salt solution d; wherein the oily organic matter c with high boiling point is one or a mixture of more than one of C 10 -C 18 organic long-chain alkyl carboxylic acid and carboxylate, or one or a mixture of more than one of other organic long-chain alkyl carboxylic acid and carboxylate with melting point not higher than 30°C and boiling point not lower than 180°C; step 3: adding oil-infiltrating fluorine source e to the oil-soluble salt solution d obtained in step 2; when the product is compound fluoride, adding an oil-infiltrating compound of A; conducting a heating reaction at a temperature not higher than 80°C to generate nanofluoride; then heating and crystallizing the nanofluoride under the protection of inert gas at heating temperature of 180-330°C and reaction time of 0.5-5 h; after cooling, centrifuging and washing the product; and separating the product of fluoride nanoparticles from the oily organic matter c with high boiling point; wherein the oil-infiltrating fluorine source e is organic or inorganic fluoride with an infiltration angle less than 65°; step 4: collecting the evaporated volatile acid a in step 2 for use in the acid dissolution process of step 1; step 5: collecting the oily organic matter c with high boiling point in step 3 for use in the reduced pressure evaporation process of step 2. step 1: taking oxide, carbonate, basic carbonate or hydroxide containing M and/or RE as raw material; adding volatile acid a to the raw material; or directly taking volatile acid salt containing M and/or RE as raw material; heating to reflux to dissolve the raw material; and converting the raw material into water-soluble salt to obtain a water-soluble salt solution b; filtering precipitates which may exist in the solution; wherein the volatile acid a is one or a mixture of more than one of hydrochloric acid, perchloric acid, hydrobromic acid, nitric acid, formic acid, acetic acid and propionic acid; step 2: conducting a decompression process on the water-soluble salt solution b in step 1 to evaporate excess volatile acid a and water which do not participate in the reaction, wherein evaporation temperature is 50-130°C and relative vacuum is - (0.01-0.09) MPa; then, adding oily organic matter c with high boiling point to continue evaporation under reduced pressure; replacing the volatile acid bound with M and/or RE, wherein evaporation temperature is 80-160°C and vacuum is 1-3000 Pa; converting all the water-soluble salt b into oil-soluble precursor salt to obtain an oil-soluble salt solution d; wherein the oily organic matter c with high boiling point is one or a mixture of more than one of C 10 -C 18 organic long-chain alkyl carboxylic acid and carboxylate, or one or a mixture of more than one of other organic long-chain alkyl carboxylic acid and carboxylate with melting point not higher than 30°C and boiling point not lower than 180°C; step 3: adding oil-infiltrating fluorine source e to the oil-soluble salt solution d obtained in step 2; when the product is compound fluoride, adding an oil-infiltrating compound of A; conducting a heating reaction at a temperature not higher than 80°C to generate nanofluoride; then heating and crystallizing the nanofluoride under the protection of inert gas at heating temperature of 180-330°C and reaction time of 0.5-5 h; after cooling, centrifuging and washing the product; and separating the product of fluoride nanoparticles from the oily organic matter c with high boiling point; wherein the oil-infiltrating fluorine source e is organic or inorganic fluoride with an infiltration angle less than 65°; step 4: collecting the evaporated volatile acid a in step 2 for use in the acid dissolution process of step 1; step 5: collecting the oily organic matter c with high boiling point in step 3 for use in the reduced pressure evaporation process of step 2.