In work examined one of the methods obtaining the dependence of the harmonic distortion from frequency in audio power amplifier for computer circuit simulation was investigated. This made it possible to assess for the first time the influence of both the form and the depth of the negative feedback on the dependence total harmonic distortion from frequency and to reveal the conditions under which an increase in the depth of the negative feedback leads to an increase in the harmonic coefficient. The study does not show the effect of each individual cascade on the dependence of the harmonic coefficient on frequency. The study was carried out at voltage gain (GV) equal to 60, 50, 40, 30 and 20 decibels, where GV =60dB corresponds to the minimum negative feedback (NF) depth, and GV =20dB to the maximum NF depth. To obtain the dependence total harmonic distortion (THD) factor THD=F(f) in the MicroCap11 simulation program, Harmonic Distortion analysis was used.