Traditional laboratory limited by time, space and other factors, further more, laboratory construction will be costly. Simulation and virtual techniques bring new opportunities to traditional teaching. This paper compare different implementations of virtual technology firstly, useing VRML technology to design virtual laboratory scene, using 3DMAX to drawn experiment equipments, using JavaBean components and flash technology to simulate the intercorrelation between human and computer., putting forward a three Layers framework of virtual laboratory system platform. Students can experiment online by web browser, which can simulate devices really.