Abstract: Based on the review of international patent technology on two shafts alignment, the important issues related with two shafts alignment in terms of three-dimensional coordinates are conducted. The laser alignment project plane of synchronous circumrotated shaft is described in three-dimen- sion. Analysis geometric problem of coaxiality error measurement is solved in terms of synchronous circumrotating posi- tion coordinates. Spatial coordinate changes of an electro-op- tical measuring device are demonstrated using experiments. Original oval curve which laser light spot on plane of perpendicular one shaft, has been changed on the plane of electro- optical measuring device. It is very clear that the angle and coaxiality error between two shafts influences the curve on plane of electro-optical measuring device.

Key words: Coaxiality, Coordinate, Laser alignment, Measurement