Abstract: By adopting single-mode laser noise-loss model which is driven by signal with frequency noise,colored pump noise and quantum noise whose real part and imaginary part are cross-correlated,we have used linear approximation method to calculate the output power spectrum and the signal-to-noise ratio(SNR)of laser system,and then have discussed the effects on the curve of SNR versus cross-correlated coefficient between real part and imaginary part of pump noise through varying intensity of frequency noise D,amplitude B and frequency Ω of input signal respectively.The results show that the intensity of frequency noise D will reduce the SNR of the output power spectrum and weaken the resonance.