A Method to purify ferulic acid and/or salts thereof, where the ferulic acid and/or salts thereof was extracted by a method of extraction, with purity inferior to 90% and in solid state; said method is characterized because it includes: i) Dissolve ferulic acid and/or salts thereof totally, with a selective organic solvent; ii) Recover and separate the solution from water insoluble impurities with the help of filters; iii) Recover the selective organic solvent by subjecting the solution to evaporation in a vacuum evaporator that allows the recovery of the selective organic solvent at a temperature between 30 and 60 °C, with a vacuum between 53,3 to 93,3 kPa (400 to 700 Hg mm); iv) Mix with water the concentrated extract of ferulic acid and/or salts thereof, from the previous step, in a ratio of 1:1, to pre-crystallize the impurities soluble in water; v) Evaporate the mixture to remove the remains of organic solvent, at a temperature of 60°C; vi) Concentrate the mixture free of solvent in an evaporator, at 30 to 60 °C, with 53,3 to 93,3 kPa (400 to 700 Hg mm) to obtain a final volume of 40 to 50 %; vii) Cool the concentrated mixture at 40 °C; viii) Let the concentrated mixture to set, 1 h, to isolate by sedimentation the water-insoluble impurities; ix) Re-heat the mixture free from impurities at 70 °C; x) Purify the re-heated mixture through a synthetic purification resin; xi) Transfer the purified mixture to a crystallizing container with cooling jacket, where the ferulic acid and/or salts thereof crystallize after 4 h of being set, at a temperature of 15 °C, with purity from 98 to 99.9 %; xii) Remove the mother liquor of crystallization from the precipitate of ferulic acid and/or salts thereof, through centrifugation at 1000 rpm for 20 min; and xiii) Dry the ferulic acid and/or salts thereof, purified, in a drying equipment with vacuum trays and inert atmosphere, for 2 h, to obtain humidity inferior to 1%, preferably. i) Dissolve ferulic acid and/or salts thereof totally, with a selective organic solvent; ii) Recover and separate the solution from water insoluble impurities with the help of filters; iii) Recover the selective organic solvent by subjecting the solution to evaporation in a vacuum evaporator that allows the recovery of the selective organic solvent at a temperature between 30 and 60 °C, with a vacuum between 53,3 to 93,3 kPa (400 to 700 Hg mm); iv) Mix with water the concentrated extract of ferulic acid and/or salts thereof, from the previous step, in a ratio of 1:1, to pre-crystallize the impurities soluble in water; v) Evaporate the mixture to remove the remains of organic solvent, at a temperature of 60°C; vi) Concentrate the mixture free of solvent in an evaporator, at 30 to 60 °C, with 53,3 to 93,3 kPa (400 to 700 Hg mm) to obtain a final volume of 40 to 50 %; vii) Cool the concentrated mixture at 40 °C; viii) Let the concentrated mixture to set, 1 h, to isolate by sedimentation the water-insoluble impurities; ix) Re-heat the mixture free from impurities at 70 °C; x) Purify the re-heated mixture through a synthetic purification resin; xi) Transfer the purified mixture to a crystallizing container with cooling jacket, where the ferulic acid and/or salts thereof crystallize after 4 h of being set, at a temperature of 15 °C, with purity from 98 to 99.9 %; xii) Remove the mother liquor of crystallization from the precipitate of ferulic acid and/or salts thereof, through centrifugation at 1000 rpm for 20 min; and xiii) Dry the ferulic acid and/or salts thereof, purified, in a drying equipment with vacuum trays and inert atmosphere, for 2 h, to obtain humidity inferior to 1%, preferably.