Bit error rate estimation of the LEO satellite channel is presented. Since it could hardly be expressed the bit error rate under the practical degradation factors in a closed form, the method to predict the bit error rate using the known moments of the degradation factors is employed. The numerical example in this analysis is provided, especially, under the effects of Traveling Wave Tube Amplifier (TWTA) nonlinearity, fading effect and intersymbol interference (ISI). Under Ricean fading channel model, in the LEO environment, the result shows the system performance is worse and couldn't be used for voice communication when the LEO satellite is located at a lower elevation angle (EL). Besides, the degradation of the effect of ISI is more prominent when the LEO satellite is located at a higher EL.