Based on block sampling and genetic algorithm we improve the image segmentation technology, and obtain the new image processing method based on image pixel block cross reconstruction, and apply this algorithm to the block and the reconstruction calculation of track and field image. In order to verify the effectiveness and reliability of block sampling and genetic algorithm, we use MATLAB to test the algorithm. Through calculation, the number of 2D block is 20, the minimum number of 3D pixel array is 1259, and the calculation residual reaches the highest, with 0.0122. When the number of 2D block is 40, the maximum number of 3D pixel array is 3875, and the calculation residual reaches the lowest, with 0.0013. Therefore, according to the needs of computer hardware conditions, we can increase the 2D block number, improve the segmentation number of 3D pixel array for track and field image, which can reduce the residual and improve the precision of calculation.