Abstract: A two-ring ferrite test system for ferrite-loaded cavities of rapid cycling synchrotron(RCS) of China spallation neutron source(CSNS) has been developed. The measurement of ferrite ring provides very important information for designing the cavities and the whole RF system. Even more, all the ferrite rings used in the RCS will be sorted based on the measurements with the test system. The cavity structure in the test system ensures the measurement reliability and repeatability with good field uniformity. A control system including LLRF control, bias current control and data acquisition has also been developed for increasing the efficiency of the test system, and it is also necessary for measurements in the frequency-sweeping mode. The preliminary cold-mode test and high-power test results in the static state are presented.