This paper proposes a variable step-size dual-mode blind equalization algorithm that runs the SMMA algorithm and the DD algorithm in parallel. On the basis of maintaining the high performance of the original two algorithms, this algorithm improves the traditional DD algorithm, runs the two algorithms in a parallel structure, and at the same time adds an error control function to control the proportion of the SMMA algorithm, reduce the steady-state error. Theoretical analysis and simulation experiments show that compared with the traditional method, ISI is reduced to -29.8 dB, and the convergence speed is improved, and the algorithm completes the convergence at about 630 symbols. After the completion of the simulation experiment, demodulation equalization of the measured signals was conducted, and the EVM was reduced to 1.69%.