Based on the physical origin of phase conjugation generated by four wave mixing, the response time of phase conjugate mirror is defined and the external cavity model for laser diode under non-instantaneous phase conjugate optical feedback is set up. Numerical analysis is given to discuss the influence of response time and frequency detuning on the characteristics of bifurcation and noise. The results indicate that the numbers and the range of chaotic bands can be restrained greatly by increasing the phase conjugate mirror's response time when the influeme of noise is considered. When the response time reaches 1.5 ns, all the instabilities of laser diode are suppressed. If noises considered, the intensity of relative intensity noise decreases by several dB or even tens dB with the increase of response time and its spectrum peak moves to higher frequency , the feedback rate for coherence collapse also increases by one order. Since the frequency detuning is smaller compared to laser diode lasing frequency by more than three orders of magnitudes, it only influences the bifurcation diagram and almost have no influence on relative intensity noise.