Abstract: Based on an equivalent circuit model of transistor autodyne,the non-resonance oscillation characteristics of the forced oscillation of autodyne are analyzed using the harmonic balance method.With different jamming signals,different frequency amplitude response properties of the autodyne are obtained.Steady-state oscillation occured on the combination of constrained oscillation and free oscillation in the instance of non-resonance oscillation.The results of simulations indicate that the amplitude of the free oscillation goes to a stable nonzero with a weak jamming signal and turns zero with a strong jamming signal,but the oscillation within the bounds of some frequencies is complex with a small(jamming) signal.