Abstract: Space robot can fly or float in the space to help or replace astronauts to perform space welding task.For a planar free floating dual-arm space robot, the path planning of welding torch position and configuration in tracking space weld is studied.On the basis of kinetic model of dual-arm space robot, the computational approach of robot arm end velocity is discussed and analyzed, and the solution of dual-arm end velocity is defined as a multi-dimentional searching problem, which is solved by introducing Genetic Algrithom to optimize calculation parameter.Finally, an algrithom of path planning of dual-arm space robot tracking space weld is proposed, which is verified and analyzed by two simulation experiments of line and arc welding seam tracking.