The invention discloses a foundation quick rammer compactor for constructional engineering. The foundation quick rammer compactor structurally comprises a hydraulic rod, a supporting plate, a tampinghammer, a hammer body, a balancing weight, a connecting wire, a shock absorber, a mobile arm, a cab, a vehicle body, a walking crawler belt and a flattening device. After the improvement, when the tamping is carried out; a worker controls the vehicle body to operate the mobile arm to adjust the hammer body; the mobile push plate is used for extruding downwards, so that the body assists the pressing plate to press the compaction hammer downwards to compact the foundation, the compaction impact force of the compaction hammer is reduced through the adjusting element and the buffer air bag, the influence of the impact feeling on construction personnel is reduced, floating and sinking around are treated through the dust suction pipe, and the working environment during compaction is improved. After the ground is hit, the pressing force of the pressing roller and the rolling wheel is adjusted through the adjusting block, the pressing roller and the rolling wheel move through the rotating shaft, the flattening wheel is assisted in flattening the foundation surface, the uneven phenomenon of the foundation is prevented, the flattening wheel compacts gravel on the ground on the foundation, and the tamping effect is improved.