An on-vehicle multiple-beam optical phased array laser three-dimensional imaging radar system relates to the technical field of radar engineering and settles problems of short-distance object detection and low imaging frame frequency in an existing laser three-dimensional imaging system. The on-vehicle multiple-beam optical phased array laser three-dimensional imaging radar system comprises a multi-beam laser module, a transmitting module, a receiving module, a central processor and a distance measuring unit. The multi-beam laser module comprises a beam splitter, a phase modulator array, a fiber amplifier array and a collimating beam spreading array. The transmitting module comprises a unidirectional glass array and an optical phased array. The receiving module comprises an optical filterarray, a double-bonding-lens array, a surface array APD array, a quenching circuit and a distance measuring unit. A ground objective area is scanned through multiple laser beams, thereby obtaining corresponding point cloud data. The obtained data are processed, thereby realizing objective three-dimensional image reconstruction with advantages of high frame frequency, high resolution and large visual field. A detecting task to a ground object is finished in real time in high speed. The on-vehicle multiple-beam optical phased array laser three-dimensional imaging radar system has advantages of high measurement speed and high measurement precision.