A method for accurately obtaining a photolithography parameter. In the method, photolithography is performed on a target carrier with different preset photolithography parameters by using a same mask pattern as a mask, to obtain a plurality of target patterns. Each of the target pattern is compared with a standard pattern to obtain an evaluation value, and the target pattern is set as a valid pattern, when the evaluation value corresponding to the target pattern is greater than or equal to a preset value. A Bosung curve is drawn by taking a line width of the valid pattern and a preset photolithography parameter corresponding to the line width as data. The photolithography parameter corresponding to a preset line width is obtained according to the Bosung curve.