A concrete construction joint impressing tool for a modular wall body comprises dowel bars and stress bars, wherein the multiple dowel bars are arranged in parallel and are connected with the stress bars, a handle is installed on the dowel bars, and the dowel bars are perpendicularly connected with the stress bars. According to the concrete construction joint impressing tool for the modular wall body, an operator can apply pressure to the dowel bars with feet by adopting a connecting structure of the dowel bars and the stress bars, the pressure is transmitted to the stress bars through the dowel bars, multiple pressing marks namely construction joints are generated on newly solidified concrete after the stress bars are stressed, operation can be finished in a standing mode, and the concrete construction joint impressing tool for the modular wall body is particularly suitable for concrete impressing construction in a narrow space. The handle is arranged so that the impressing tool can be moved conveniently.