The invention relates to a separation testing method for axial force, bending moment and torque of load for a drilling tool. The method comprises: selecting three points at equal intervals on the cross section of a cylinder rod with the same size to a drilling tool; respectively placing strain sensors at the three points to measure the axial strain; placing a strain sensor at other directions of any point to measure the strain of the direction; establishing a threaded rod model and a cylinder rod model in finite element simulation software so as to obtain the difference between the axial stress value of the drilling tool and the axial stress value of the cylinder rod and the shear stress ratio of the drilling tool to the cylinder rod on the same slope; and then obtaining the axial force, the bending moment and the torque of the drilling tool through calculation. Compared with the prior art, the separation testing method for axial force, bending moment and torque of load for a drilling tool takes the drilling tool as a product obtained by overlaying screw threads on the cylinder rod with the same size to the drilling tool, and can realize a separation test of the axial force, the bending moment and the torque of the composite load by measuring the axial strain at the three points and the strain of other directions from any point, and is simple, accurate and reliable.