The paper introduced some methods about CLG steel cylinder non一destructive inspection,and appeared the superiority of the sofar shoot the exanination on the CLG steel cylinder non-destructive in- spection. At the same time, the paper described some questions need to pay attention and characteristics in the applications of rapid detection of on一line CLG steel cyliner and put up some improvanents methods; the author establish system of a simple data acquisition，analysis and processing. By using the system, the user not only can realize signal acquisitions and the frequency range of analysis but also can realize wavelet denoising. The results show that rapid detection of on line CNG steel cylinder is the feasible.