The invention provides an optical sub-module detecting machine and detecting method. Through the detecting machine, optical sub-modules which include but are not limited to an optical transmitting sub-module and an optical receiving sub-module are fully automatically fed and detected, and good and bad products can be respectively discharged. The detecting machine comprises an optical fiber end face detecting and cleaning and optical fiber inserting and coupling mechanism, a full-automatic feeding mechanism, a feeding mechanism assembly, a discharging mechanism assembly, a high-accuracy station transferring mechanism (such as a rotating mechanism and a linear reciprocating conveying mechanism), a workbench, a control panel, a closed loop automatic detection control system, a human-machine conversion interface, a protecting cover and a fault alarming system. The optical sub-module detecting machine and detecting method make up for the blank in the field of full-automatic detection of optical sub-modules, and solve the problems that because of manual detection or semi-automatic detection, the detecting accuracy of parts to be detected is not high, the detecting efficiency is low, and the detecting cost is high.