The invention relates to a well-sinking method on a muddy ground. The method comprises the following steps: S1, manufacturing a first section shaft provided with a wellhole; S2, mounting a hydraulic gate in the lower end of the wellhole; S3, sinking the first section shaft under the action of self weight; S4, adjusting a hydraulic valve to control the sinking speed of the shaft and correcting theshaft; and S5, mounting the shaft and sinking the follow-up shafts in position. In the shaft sinking process, a lifting propeller which drives the shafts to ascend and a descending propeller which drives the shafts to descend are connected to the uppermost section shaft. When the shafts still sink suddenly after all hydraulic valves are closed, sudden sinking is prevented by means of a force generated by the lifting propeller to lift the shafts. When the descending speed of the shaft is still lower than an expected value when all the hydraulic valves are opened, sinking of the shaft is accelerated by means of a force generated by the descending propeller to press the shaft, and the descending speed is also controlled by means of the propeller. During construction in soil, the problems thatthe descending speed of the shaft is unlikely to control and the shaft sinks suddenly are solved.