The invention relates to a vibrohammer with internal vertically-arranged eccentric moment adjusting mechanism. The main body comprises a power-driven inputting member, a vibration exciter case body, a left and right dual shaft directional inertial vibrator and an eccentric moment adjusting mechanism; the left and right dual shaft directional inertial vibrator is composed of a driving shaft, a driven shaft, a shaft sleeve, a front and back synchromesh gear and four pairs of eccentric bodies; the main body of eccentric moment adjusting mechanism is arranged at back inside the vibration exciter case body, and is composed of a steep-lead thread spline shaft section arranged at the tail ends of the driving shaft and the driven shaft in an extending way, thread spline adjusting sleeve respectively provided with non-spline ends, a synchronous carrier gear, a steep-lead thread spline sleeve and a controlling device consisting of a thrust bearing, an echelonment small shaft, a nut with cap, a bearing seat, a connecting board and a hydraulic cylinder. With the eccentric moment adjusting mechanism arranged at back inside the vibration exciter case body to be directly connected with the driving shaft and the driven shaft, defects of existing external vibrohammer can be overcome, and the invention has the advantages of small volume, light weight, low production cost, convenient use and the like.