Studying the linear parallel drawing based on Bresenham, this paper calculates the average number of pixels in each scan line when the slope k belongs to (0,1/2) based on Probability, and finds that three-quarters of the drawing time can be saved with this method. According to the theoretical analysis, combined with classical Bresenham algorithm for generating line, it realizes a parallel Bresenham algorithm for generating line, and the results with this method are the same as the windows drawing program and the classic Bresenham drawing linear algorithm. It is very important to multi-point parallel rendering for scan line and is easy to design hardware which can enhance the response to real-time drawing.