Abstract: To solve the performance degradation of voltage-controlled magnetic anisotropy magnetic tunnel junction (VCMA-MTJ) and its reading circuit caused by soft breakdown, a modified electrical model of VCMA-MTJ was established based on the soft breakdown mechanism, and a VCMA-MTJ reading circuit with a fixed reference resistance and a VCMA-MTJ reading circuit with a reference resistance control unit were designed to study the effect of soft breakdown on the resistance R_t, tunnel magneto-resistance ratio M, and soft breakdown time T_s of VCMA-MTJ as well as the read error rate of the VCMA-MTJ reading circuit. Results show that both R_t and M decrease with the increase of the stress time t due to the soft breakdown. T_s increases slowly with the increase of the thickness of the oxide layer t_ox and decreases rapidly with the increase of the pulse voltage V_b. T_s in the parallel state is shorter than that in the anti-parallel state, and it takes less time for the VCMA-MTJ in the parallel state to reduce M by 50%. The error rate of reading "0" in the VCMA-MTJ reading circuit with fixed reference resistance can be effectively avoided. However, the error rate of reading "1" increases with the increase of t. The VCMA-MTJ reading circuit with reference resistance control unit can not only keep the correctness of reading "0", but also effectively improve the error rate of reading "1" by up to 54%, showing the ability to weaken the effect of the soft breakdown on the VCMA-MTJ reading circuit to a certain extent.