An aromatic amine androgen receptor (AR) and BET targeting protein degradation chimera compound and its use. Specifically provided is a compound represented by formula I. Experimental results show that the compound can target and degrade both AR and BRD4, and down-regulate the expression of AR and BRD4 proteins; the compound can inhibit the proliferation of a variety of prostate cancer cells; the compound can inhibit the proliferation of a prostate cancer cell line LNCaP/AR, which overexpresses the AR, and can achieve a good inhibition effect on a prostate cancer cell line 22RV1, which is resistant to a marketed prostate cancer drug (enzalutamide); the compound also shows good metabolic stability, and has a good application prospect in the preparation of an AR and/or BET protein degradation targeting chimera, and a drug for the treatment of related diseases regulated by the AR and BET.