The invention relates to a system for testing the performance of an ISM (industry, science and medicine) frequency range communication product and a testing method, and in particular relates to a system for testing the performance of a communication product and a testing method, and the problem of low testing accuracy of the existing method for testing the performance of the ISM frequency range communication product is solved. In the system provided by the invention, N transmitters to be tested and a reference transmitter are accessed to a chain through a No.1 multi-way switch and connected with N receivers to be tested and a reference receiver after passing through an adjustable attenuator, a fixed attenuator, a combiner and a shunt; and an oscilloscope displays the waveform of each receiver. In the method provided by the invention, the performance detection of the ISM frequency range communication product to be tested is realized by testing the sensitivity of the receivers to be tested, the transmission power of the transmitters to be tested, the same-frequency interference-resistant performance of the receivers to be tested, the multi-address interference-resistant performance of the receivers to be tested and the high and low temperature-resistant performance of the product to be tested. The invention is suitable for testing the performance of the ISM frequency range communication product.