A sound isolator with axisymmetric periodic groove structures is given for eliminating drill collar wave.Sound isolation effect with different groove's depth (H),length,number,section shape and thickness of the drill collar is studied.With rectangle section shape,decreasing thickness of the drill collar and increasing H,isolation effect of the acoustic isolator can be increased.It can get a maximum of 36 dB sound attenuation which meets requirement of the sound isolator in LWD.