Aiming at the performance evaluation of mixed-mode sensing interface of the integrated-sensor RFID system, an integrated-sensor RFID system was constructed. Then the mechanism of performance evaluation of mixed-mode interface was analyzed. According to the validity and reliability principle, a mixed-mode interface performance testing model was established. Moreover, a Plug-and-Play performance testing method was presented. Finally, the physical platform was set up to test the reading speed and the recognition rate indicator in Plug-and-Play process. Results showed the reading speeds of two STIM maintained at around 656.56ms and 645.24ms steadily during Plug-and-Play process whose Bit Error Rate was 10e-9. Experiments indicate that effective transverse comparison of performance of similar products could be implemented by the proposed method in static environment as well as dynamic environment.