Optical calibration and testing device for machine tools

An optical calibration and testing device for machine tools comprising:

• a light source unit having a foundation for fixing a light source to provide at least one laser light;
• a horizontalness testing device which is a leveling instrument installed on said foundation for adjusting an angular position of said foundation;
• a beam splitting device for splitting said laser light into two beams;
• and
• a plurality of photo detectors with their receiving surfaces aligned with an incident beam so as to receive a light beam,
• wherein said light source emits the laser light into said light splitting device so as to split said laser light into said two laser beams as a transmission light and a reflection light perpendicular to each other, using said two laser beams to hit a first and a second photo detectors placed on a moving terminal in the direction perpendicular to each other, a verticalness error at said moving terminal is figured out whether the position of an initial light spot coincides with that of a testing light spot or not.