A card for testing functions of the card interface of an electronic device is provided. The testing card includes a converting circuit, a latch circuit, a data processor, a signal generator, an oscillation combination circuit, and a reset circuit is provided. The converting circuit is coupled to the card interface. The latch circuit receives the data signal fed in from the card interface, latches the data signal and outputs it to the data processor afterwards. Having received the signal sent from the converting circuit and the latch circuit, the data processor is able to proceed with testing. The signal generator can output the mode selection signal and the interrupt signal to the card interface to test the functions of mode selection and interrupt signals. Furthermore, the oscillation combination circuit can generate a wait signal and feed the wait signal to the card interface for the wait test.