USB(Universal Serial Bus) is currently the most popular interface standard using on computer peripheral devices. In order to develop device driver for the USB device in advance, we introduce how it use DSF(Device Simulation Framework) to simulate USB devices that are not physically existed. The steps of developing a simulated device mainly include: build the dynamic link library for the device in order to describe the functional feature of the device using a COM complied language, then using a script file to describe the behavior of the simulated device. Above the operating system level, there is no difference between the simulated devices and the physically existed devices, and the simulated device can be used for developing and testing the drivers or the applications.