Radar target trace estimation is an important application of Kalman filtering. This paper uses the CV model in discrete Kalman filtering to simulate the trace of moving target in 3-D space. We generate the real trace under orthogonal set, transform the observe trace under polar set to the orthogonal set, then apply it to Kalman filtering. We analyze the performance using the mean error and deviation of the observation, prescreen and filtered trace, the effects of original values and system parameters to Kalman filtering are also presented.