At present, Nd∶YAG laser feedback interferometer has been achieved. However, in the actual application some deficiencies still exist in this system. Basic parameters of Nd∶YAG microchip laser are measured and the instruction of the invisible light with the wavelength of 1064 nm is realized, with the improvement of the measurement range and the compensation of air refractive index, by combining red indicating device, collimating and beam expanding device and the refractive index of air compensating system with the original Nd∶YAG laser feedback interferometer. So Nd∶YAG laser feedback interferometer is more convenient to use with a broader application and higher accuracy.