In this paper the asymmetric bistable system excited by binary aperiodic signals is taken as a model and the average symbol error rate is regarded as an index to study stochastic resonance (SR) phenomenon. Firstly, the SR driven by binary signals under alpha stable noise is studied. Secondly, the interplay between the alpha stable noise parameters alpha, beta, and the system parameters a, b, r on the resonant output effect is explored. The results show that weak binary signals detection can be realized by adjusting the system parameters a, b and r. The optimal values solved by these parameters can make the system produce the best SR effect. For a certain a or b, there is an optimal value under different or. For the parameter r, there is an optimal value under different alpha, and there are several optimal values under different beta. Moreover, when alpha or beta is given different values, the evolution laws in asymmetric bistable SR system excited by binary signals are same. The results lay a foundation for realizing the adaptive parameter adjustment in asymmetric bistable SR system with alpha stable noise.