The invention discloses a multifunctional direct shear apparatus which comprises a bracket, a longitudinal power device, a transverse power device, an upper box body and a lower box body, wherein the longitudinal power device and the upper box body are fixedly mounted on the bracket; the upper box body and the lower box body are arranged below the bracket; the lower box body can slide relatively to the upper box body; a through hole is formed in the upper box body; a groove corresponding to the size and the position of the through hole is formed in the lower box body; the power output end of the longitudinal power device can be fed into or withdrawn out from the through hole; the power output end of the transverse power device is propped against a side surface of the lower box body. When the multifunctional direct shear apparatus is adopted for shear force testing, under the action that the lower box body is subjected to horizontal force of the transverse power device, as no gap is formed between a soil sample and the through hole and the groove, the force exerted to the soil sample by the transverse power device is constantly perpendicular to the soil sample, the testing strength can be relatively approximate to actual testing strength, small errors can be caused, and the accuracy is high.