The invention discloses an industrial robot space intersecting curve welding offline programming method. The method comprises the steps that firstly, an arc welding robot and a welding workpiece three-dimensional model are guided in, two peripheral hook faces of a welding line are formed through mouse pickup, a cut plane set is created inside a workpiece coordinate system, and node pose information of the welding line is extracted; according to the node pose, position and posture discretization are achieved along the curve of the welding line, and then welding line trajectory planning is achieved through coordinate conversion; then, a joint angle sequence needed in the robot motion process is obtained through robot inverse kinematics, and motion simulation is achieved; finally, according to language rules written by corresponding robot motion control program codes, a corresponding program file is generated. By adopting an open source VTK visual tool magazine, offline programming independent development is achieved, the method does not dependent on third party CAD software, the track of the welding line can be generated only through mouse picking, no complex external data computingor guiding-in process is needed, the man-machine interaction is good, and the needed robot program can be rapidly generated.