Abstract: Microwave cavity, which determined the accuracy of the frequency identification of the rubidium atomic clock, is the key component of the rubidium atomic clock.In order to improve the frequency precision and miniaturization of the microwave cavity, we carried out research and design for small magnetron microwave resonator with TE₀₁₁mode, through theoretical research and simulation analysis.We carried out the experimental test for the microwave cavity, the experimental results show that the microwave cavity fully meets the requirements of the high performance rubidium atomic clock and improves the performance index, the frequency stability of the experimental system is 7.83×10^-13@1 s、1.97×10^-14@1 000 s.