Traceable measurement of 2-D Line Scale templates needs high resolution aim at the crosswire. In the 2-D dynamic photoelectric microscope, the image of crosswire is illuminated on two sets of slits which are mutually perpendicular. There are two slits in each set, which have the same width with the image of crosswire. And the distance between the two slits in width direction is also the same size. When the template moves in one of the directions, the image of crosswire will appear in the two slits successively. The luminous flux of the slits will change one after another, which means there is a phase difference between the photoelectric receivers of corresponding slits. And the signal processing system judges the aiming moment using those two signal. In this way, 2-D Dynamic Photoelectric Microscope can realize high resolution 2-D collimation.