A high precision subpixel detection algorithm based on image enhanced local up-sampling sum-squared difference(IE-LUSSD) is studied to improve the anti-interference ability of linear motor position detection to different light intensity. Firstly, according to the motion characteristics of one-dimensional rigid body translation of linear motor, a motion position detection system based on line-scan camera and aperiodic fence image is designed. The line-scan camera is fixed on the mover and follows mover motion to collect signal sequences. Secondly, the gray-scale linear transform image enhancement algorithm is used to preprocess the collected signal sequences to enhance the image information. Then, SSD algorithm is adopted to obtain the integer-pixel displacement between adjacent signal sequences. In order to further improve the measurement accuracy, frequency domain matrix multiplication discrete Fourier transform is applied to up-sample the peak neighborhood of the correlation function of adjacent signals to refine the peak curve. Finally, the effectiveness of the method in different light conditions is verified by building an experimental platform for motion position detection. Detection accuracy of the proposed algorithm can reach 0.01 pixels and actual position detection error of the mover is within 0.025mm.