Abstract: An experimental beam correcting optical system for laser diode is established for compensating astigmation and circulating the elliptical beam.The system is combined by two prisms,a cylindrical lens and a collimating lens.The results show that the divergence angle of the laser beam can be corrected to less than l mrad,and even reach diffraction limited.This system possesses the advantages of low cost,low power loss,simple structure,and it is convenient to operate.