A projection display uniformity compensation method, comprising: S11: acquiring an original image data input in a display unit and a brightness loss coefficient of a compensation region of the display unit, where said brightness loss is due to attenuation through a projection lens of a projection system of the display unit, and where a grayscale value of the original image data corresponding to an arbitrary point A in a non-compensation region of the display unit is u, and that corresponding to an arbitrary point B in the compensation region of the display unit is v; S12: acquiring values t1 and t2, such that t2/t1=f ∗ a/(1-a), where t1+t2=T, wherein a is the acquired brightness loss coefficient and f is a pre-stored value in a storage unit, where 0<f≤1; S13: acquiring values m and n, such that m ∗ t1/T + n ∗ t2/T = u ∗ t1/T, and where at least two values among m, n and u satisfy a predetermined relationship, wherein the predetermined relationship is given by one of the following: n=m ∗ x, u=m ∗ x or u=n ∗ x, wherein x is a pre-stored value or a value input by the user; S14: determining a full region image data and a compensation image data based on m, n and v, where a grayscale value of the full region image data corresponding to the point A is m and that corresponding to the point B is v, and where a grayscale value of the compensation image data corresponding to the point A is n and that corresponding to the point B is q, where q≥v, and besides q and v satisfy a predetermined relationship, wherein the full region image data is the same as the original image data, while the compensation image data is the same as the original image data in the compensation region but is zero in the non-compensation region; and S15: within a time period T when a frame of the image data is being modulated, wherein each frame of the image data is formed by the full region image data and the compensation image data, within a time period t1, acquiring an original light from an original light source of the projection system and modulating the original light according to the full region image data by an optical modulator unit of the projection system, and within a time period t2, which is a time period within the time period T other than the time period t1, acquiring a compensation light from a compensation light source of the projection system and modulating the compensation light according to the compensation image data by the optical modulator unit. S11: acquiring an original image data input in a display unit and a brightness loss coefficient of a compensation region of the display unit, where said brightness loss is due to attenuation through a projection lens of a projection system of the display unit, and where a grayscale value of the original image data corresponding to an arbitrary point A in a non-compensation region of the display unit is u, and that corresponding to an arbitrary point B in the compensation region of the display unit is v; S12: acquiring values t1 and t2, such that t2/t1=f ∗ a/(1-a), where t1+t2=T, wherein a is the acquired brightness loss coefficient and f is a pre-stored value in a storage unit, where 0<f≤1; S13: acquiring values m and n, such that m ∗ t1/T + n ∗ t2/T = u ∗ t1/T, and where at least two values among m, n and u satisfy a predetermined relationship, wherein the predetermined relationship is given by one of the following: n=m ∗ x, u=m ∗ x or u=n ∗ x, wherein x is a pre-stored value or a value input by the user; S14: determining a full region image data and a compensation image data based on m, n and v, where a grayscale value of the full region image data corresponding to the point A is m and that corresponding to the point B is v, and where a grayscale value of the compensation image data corresponding to the point A is n and that corresponding to the point B is q, where q≥v, and besides q and v satisfy a predetermined relationship, wherein the full region image data is the same as the original image data, while the compensation image data is the same as the original image data in the compensation region but is zero in the non-compensation region; and S15: within a time period T when a frame of the image data is being modulated,