The invention discloses an optical parameter oscillator array coherent beam combination system and an active control method. According to the nonlinear correlation of optical parameter oscillator array beam phases, the fundamental-frequency optical phase is adjusted by using a phase modulator arranged at the front end of an amplifier so as to lock a phase between middle-infrared band optical parameter oscillator array beams, and active phase locking coherent combination of middle-infrared light waves is realized. The optical parameter oscillator array coherent beam combination system is compact in optical path structure, high in reliability and small in size. Compared with a mode of carrying out fundamental-frequency light combination and then applying adopted in an existing middle-infrared solid-state laser coherent combination technology, the optical parameter oscillator array coherent beam combination system can solve a problem of high photo-thermal damages of the phase modulator and optical parameter oscillation nonlinear crystals to a great extent, and the power extensibility of middle-infrared combination beams can be greatly improved.