The flexible transmission of the laser energy plays an important role in the development of lasers.In this paper,based on the advantage of flexible structure design and preparation o f microstructure fibers,a kind of pure silica microstructure fiber used for the transmission of high power laser energy is designed.This kind of fiber has a cladding with double air holes,and the e xter nal diameter of the fiber is 180μm with a core diameter of 84μm. Experiment measurements show that the transmission loss of the semiconductor la ser operating at the wavelength of 980nm is 6dB/km and that of the YAG laser operating at the wavelength of 1064nm is 7dB/km,and the lowest loss can reach 1dB/km at the wavelength of 935nm,When the bending radius of the fiber is about 0.25cm,the additional bending losses are 0.28dB/circle and 0.4dB/circle at the wavelength s of 980nm and 1064nm,respectively. The actual mode field area is 2951.71μm^2at the wavelengt h of 980nm,which is consistent with the theoretical value of 2951.4μm².The results indicate that this kind PC F has the advantages of simple structure,easy preparation,good flexibility,low nonlinearity,low loss and high energy damage th reshold.It can be an ideal medium in high power laser energy flexible transmissi on system.