The trajectory planning optimization can improve the performance of robot, and therefore the artificial life system method is applied in arc trajectory planning of robot. Firstly, the mathematical model of arc trajectory planning of robot is analyzed. Secondly, the basic theory of artificial life system is studied, and the corresponding algorithm procedure is designed. Finally, the simulation analysis is carried out, and the optimal trajectory of robot is obtained, and results shown that the artificial life system optimization method can be applied in the trajectory planning of robot effectively.