The invention provides a method for arranging a jacking force of a jacking pipe of a rectangular open caisson eccentric jacking, which comprises the following steps: (a) obtaining soil parameters and open caisson parameters of a region of a working area applying the rectangular open caisson; (b) calculating soil pressure along each direction of the open caisson according to the soil parameters and the open caisson parameters; and (c) calculating an allowed jacking force for eccentrically jacking of the jacking pipe according to a distribution mode of the soil pressure and the soil pressure, and causing a jacking force required by the advancing of the jacking pipe to be less than the allowed jacking force for eccentrically jacking. According to the method provided by the invention, the soil parameters of the working area are confirmed according to the geological data and test data; the soil pressure acted on each direction of a working well is solved by utilizing the jacking force of the pipeline, a soil pressure formula and a given soil pressure distribution shape; the allowed jacking force for eccentrically jacking of the jacking pipe of the working well is finally calculated; and according to the allowed jacking force, the jacking pipe of the rectangular open caisson can be safely arranged.