In the process of photonic microwave communication ,the bandwidth is narrowed due to the impact of noise ,reducing communication efficiency. In order to optimize the quality of photonic microwave communication ,a cascade filtering method for photonic microwave signals based on feedback mechanism is proposed. After removing the ambiguity of the signal using morphological erosion and dilation ,the signals with high similarity are clustered into con- tinuous regions to complete microwave signal denoising. The Kalman filter is selected to filter the microwave signal measurement noise for the first time ,and the mean filtering and dual threshold output scheme are used to filter the mi- crowave signal generated under dual photoelectric feedback for the second time. Through the cascade processing of two filters ,different clutter in the microwave signal is removed ,and the cascade filtering of narrow linewidth photonic mi- crowave signals is realized. Experimental results show that the proposed cascaded filter has a small amplitude of wave motion ,can stably output the filtering results ,and the attenuation characteristics of the cascaded filter at different tem- peratures are relatively stable.