Abstract: The time recursive averaging noise power spectrum estimation algorithm had the problems of tracking delay and estimation error in non-stationary noise environment. This paper proposed a new spp(speech presence probability) estimation algorithm which was a core part of noise power spectrum estimation algorithm. Firstly, the ratio of energy in time domain to spectrum entropy in frequency domain was used as a new feature to obtain the spp of current speech frame; then the estimation of spp was smoothed by the double smoothing coefficient; finally, the estimated noise power spectrum was obtained by combining with time recursive averaging algorithm. This algorithm made full use of the feature information of frequency point to control the spp and track the noise changes adaptively. The simulations show that this method can accurately track the noise power spectrum and quickly respond to the noise power spectrum changes in the air-ground communication environment. Integrating it into speech enhancement system can improve speech quality and reduce residual noise.