The laser attenuation device has always been an important component of the LIDT system,the attenuation adjustment ability of the laser attenuation device directly affects the performance of the testing system.The continuous attenuation device of high energy laser is achieved by combining polarization cube with rotating half wave plate,when the angle of the rotating half wave plate changes from 0°to 45°, the transmissivity of the attenuator changes from 99.9% to 0.3%.This design scheme reduces the volume of the attenuation device while achieving continuous adjustment of the transmissivity.Adopting optical devices with large aperture and high damage threshold, the maximum single pulse energy that the system can withstand is 2J@1064nm. The attenuated energy is tested by using a Ophir PE50BF-DIF-C pyroelectric energy sensor,the results show that the laser energy transmissivity can be continuously adjusted within the range of [0.3%,99.9%]. Using Beamtech China SGR20 laser, it can work stably with the power density of 2J@1064nm whose experimental results meet the design re-quirements. Compared with the traditional optical variable attenuator,this design has the advantages of large dynamic regulation range, stable attenuation and continuous regulation.