Abstract: The response methods for underwater acoustic target system are typically classified into two categories: the simultaneous receiving-transmitting method and the storage-retransmission method. The simultaneous receiving-transmitting method is widely employed due to its real-time capabilities. However, the transmitted signal may also be captured by the receiving transducer after propagating through the shell and water, leading to acoustic crosstalk and degrading the transceiving performance. This paper focuses on the nonlinear interference present in the acoustic crosstalk path and proposes a convex combination algorithm based on the normalized least mean square (NLMS) filtering structure and the Chebyshev expansion-based nonlinear filtering structure. The joint parameter is optimized to reduce the convergence time at the upper and lower boundaries, thus achieving rapid convergence and a low steady-state error for nonlinear systems. Compared with the NLMS algorithm, the acoustic crosstalk suppression performance of single-frequency signals and frequency-modulated signals processed with the proposed algorithm is improved by 6 dB and 8 dB, respectively. In comparison with the Chebyshev expansion-based nonlinear adaptive filtering algorithm, the number of iterations required to reach steady state is reduced by 33% and 20%, respectively. The results indicate that the algorithm demonstrates superior modeling ability and faster convergence speed in addressing the nonlinear characteristics of acoustic crosstalk paths, effectively mitigating the nonlinear issues prevalent in acoustic crosstalk.