For the problem of the impact of the position sensitive detector(PSD) slanting installation on spot position,based on the condition that the energy of the incident light is a Gaussian distribution,a mathematical model of this distortion error of the spot position is established and simulated.

Then the accuracy center of spot was resulted from the spot image obtained above by means of improved subpixel spot center location,which is at the level of sub-pixel.

It is found that laser beam size has an important influence on the tempe.

In the paper we introduce the structure,operational principle and critical skills of the testing system for the laser beam through atmosphere.

To measure the laser facula in the far field using detector array,three requirements-laser energy density,the size of the array and the space be- tween detectors,are analyzed in the paper.