The invention discloses a space positioning system for intelligent assembly. The space positioning system for intelligent assembly can carry out space positioning on target objects which are complex in shape. The space positioning system for intelligent assembly comprises a robot control cabinet, a robot module, a 3DL camera, an image processing module, an algorithm calculating module and a positioned target object. The invention further discloses a space positioning method for intelligent assembly. The space positioning method for intelligent assembly comprises the steps of (1) building a user coordinate system and a tool coordinate system of the 3DL camera, (2) calibrating the 3DL camera in the user coordinate system, (3) taking eight photograph points in the edge of the target object to photograph, (4) carrying out binarization processing on photographed images of each point, and obtaining feature points of each photograph point, (5) extracting space position information of each feature point in the user coordinate system, (6) transmitting the space position information of each feature point in the user coordinate system to the robot control cabinet, and (7) calculating a space position coordinate system of the target object according to the space position information of the eight feature points on the target object.