By using inverse grating technology, improving the design of data input module in virtual welding system. We analyzed and accomplished the method of data input, taking into account the weldment needs to make a dynamic changes in the welding process, we design the static and dynamic data input modules. Through running some instances of the program, we have proved that, with the corresponding improvement of the inverse grating technology, the design of data input module in the virtual welding system has achieved good result.