A new configuration with single resonator cavity for both pump laser and optical parametric oscillator(OPO)is proposed, which make an improvement on output beam quality and the OPO resonance mode matches with funda－ mentalwave resonance mode. A compact anti－maladjusted OPO laser has been developed using a directional prism cavity and a Cr∶YAG crystal oriented itsBrewster angle as a passive Q2switch. An output pulse energy of 8mJ , repetition rate of 1 /6 Hz at 1. 57μm with the beam divergence of 5. 5mrad is obtained.