The invention provides a miniaturized underwater manipulator position angle measuring method. Based on a three-dimensional position measuring apparatus formed by installing three stay rope displacement sensors, a measuring coordinate system (O-XCYCZC) is established, and a base coordinate system (O-XYZ) is established at a manipulator installation fixed point. The principle of the method is as follows: actual value coordinates of the tail end of a manipulator under the measuring coordinate system are obtained through the three-dimensional measuring apparatus, the actual value coordinates are converted into the base coordinate system through coordinate conversion, and motion position errors of the tail end of the manipulator are obtained through comparison. The underwater manipulator position angle measuring method provided by the invention is convenient and simple in measuring process, concise in calculation processing process and low in cost, thereby being suitable for three-dimensional position measurement and tail-end angle precision measurement carried out by an underwater manipulator in a pool environment.