In order to achieve the high precision mapping between digital micromirror device (DMD) micromirrors and CCD pixels in high dynamic range imaging system based on DMD, three different pixel-level mapping algorithms are put forward. The high dynamic range imaging system based on DMD is introduced, and the mapping principle and necessity are analyzed. The proposed algorithms are used to map, including the direct linear transformation algorithm, nonlinear distortion polynomial fitting algorithm and back propagation neural network algorithm. And the theoretical methods are combined with the imaging system. The corresponding parameters are obtained and the error data are calculated by image testing. The error of fitting polynomial distortion mapping algorithm is minimum, and the root mean square error is 1.02 pixel, which can reach the pixel-level error. This algorithm fits the partial distortion error mapping at pixel-level and meets the needs of the imaging system.