The invention belongs to the technical field of underground engineering construction, and particularly relates to an overall construction method for a soft soil area mud-water balance open caisson station. The overall construction method comprises the following steps that (1) a counterforce frame system is constructed; (2) cutting edge sections are constructed on the ground, and a mud-water control system and a locking device are mounted; (3) a formwork framed bent on the lower part of a bottom plate is demounted, a soil body on the lower part of the bottom plate of the cutting edge sections is pumped and discharged through the mud-water control system, and the cutting edge sections are sunken to the control elevation through the counterforce system; (4) then the locking device is utilizedto lock the cutting edge sections, and then a first open caisson section is constructed; (5) the soil body on the lower part of the bottom plate is pumped and discharged through the mud-water controlsystem, under the effect of the counterforce frame system, the first open caisson section is sunken and then locked till a second open caisson section structure is constructed to the control elevation; and (6) a counterforce frame and a locking system are demounted and recovered. The construction method is simple in form, full-automatic construction can be conducted on the soft soil area underground station, the construction period can be effectively shortened, the influence on the surrounding environment is reduced, and meanwhile, the construction cost of engineering is lowered.