Abstract: For high-speed weak targets, a fast method of target parameter estimation is presented in this paper. After analyzing the factors which influence high-speed target,s range migration, it pointed out that the range migration exhibits a straight line with accumulation time. Then, using the feature of Hough Transform (HT) to detect straight line, the relationship between the parameters of HT and initial distance and initial radial velocity are analyzed and an improved method is proposed based on Parallel HT (PHT) which can improve operation speed and meet the needs of real-time processing by taking advantage of its parallel principle. Finally, the algorithm flowchart is given and the validity of this algorithm is verified with the simulation results.