Stochastic Resonance (SR) of an integrateandfire neuron model with threshold subject to synaptic noise and input signal was investigated. The amplitude gain of the output signal was obtained by the method of average. Numerical simulation shows that the evolution of the amplitude gain with regard to the input frequency is nonmonotonous in different intensity, correlation time and asymmetry of the synaptic noise. Those show that SR occurs during neuronal spiking driven by synaptic noise and period input.