To avoid the time-consuming match of multiple feature points and the difficulty in getting the full pictures of Long Shaft Part(LSP) in the process of measuring its 3D pose using non-orthogonal binocular stereovision, a method for measuring 3D pose of assembly end of LSP based on orthogonal binocular stereovision is presented. The pictures of assembly end of LSP are taken individually at the same time by two cameras whose optical axes are perpendicular to each other and processed by method of sub-pixel respectively, and then the position and posture of assembly end of LSP in the image coordinate systems of two cameras can be obtained. The 3D pose of assembly end of LSP can be acquired from the information fusion of position and posture of LSP in two image coordinate systems according to the model of orthogonal binocular stereovision. Experimental result shows that the 3D pose of assembly end of LSP can be measured rapidly and precisely by orthogonal binocular stereovision consisting of two CMOS cameras. Since only one feature point needs to be matched in this method with simplicity and low calculation cost, it can be applied to the rapid assembly of precise LSP with robots guided by machine vision.