Conversion interface applied to OBD interface and conversion system of the OBD interface

The invention relates to the conversion interface applied to an OBD interface and the conversion system of the OBD interface and belongs to the vehicle detection field. The conversion interface comprises a change-over switch, a conversion socket and an interface tail line. The conversion socket is used for connecting a vehicle-mounted automatic diagnosis system OBD interface. The conversion socketcomprises several pairs of sockets corresponding to several pairs of pin positions which need to be converted in the OBD interface. The first end of the interface tail line is connected to target sockets in the several pairs of sockets. The target sockets are a pair of sockets corresponding to a pair of pre-assigned pin positions in the OBD interface. The second end of the interface tail line istaken as the I/O end of the conversion interface. When being selected to a target pin, the change-over switch is used for connecting the first end of the interface tail line and the two sockets corresponding to the target pin