The trajectory safety characteristic of space rendezvous was studied. First of all, the quantitative performance index of space rendezvous trajectory safety was proposed. The 3σellipsoid of relative position dispersal resulting from the navigation errors and control errors was investigated to describe quantificationally the relative trajectory safety between chaser and target vehicles. And then the orthogonal design of experiment method was adopted to analyze the influence of the transfer time, the number of impulses, and the intervals of impulses on the trajectory safety characteristic. The results show that the transfer time is the most significant among all the factors, the number of impulses is the secondary, and the interval influence is very small. Finally, the influence of initial rendezvous condition was analyzed by numerical simulation, and the results illustrate that -R-bar coplanar rendezvous makes the trajectory safety index the smallest. Furthermore, the influence on fuel consumption was analyzed, and the effect is opposite to that on safety index. The study points out the direction of the design of safe rendezvous trajectory, and provides the way to design the multi-objective optimal rendezvous trajectory.