The velocity of industrial robots can be improved by multi-path smooth transition of task space. Under the path length constraint of the asymmetric S-curve acceleration/deceleration control, known path tansition points with non-zero velocity and the adjustable radius parameters are used as a reference to obtain optimized transition velocity between multi-path segments according to the changes of adjacent trajectory segments length, and arc smooth transition is used between adjacent path segments. The asymmetric S-curve acceleration/deceleration control is adopted for complete path segments. In order to improve the versatility of the algorithm, the velocity functions are simplified according to the characteristics of the S-curve acceleration/deceleration zone function. Experiments are carried out on the real-time control system platform of 6 degrees of freedom industrial robots. The results show that the efficiency of the algorithm can be improved by more than 22.03% compared with the traditional acceleration/deceleration control algorithm, and smooth transition of velocity and modification of trajectory between the multi-path segments can be realize.