We report a stochastic resonance with the signal-to-noise ratio gain in a monostable system, by the fourth-order Runge-Kutta method, and on some occasions the signal-to-noise ratio gain exceeds 1. Tuning the parameters in the monostable stochastic resonance system can change the signal-to-noise ratio gain. This research result is the latest development of the monostable stochastic resonance, and has potential applications in the signal detection, processing and communications.