In automatic ultrasonic testing of the cylinder workpiece,the detection methods of radial inclined detection and eccentric oblique probe are used mainly.At present,the probes group can not be adapted to various specifications or surface states very well. Poor coupling is easy to cause bad detection effect.By improving the probes combination, improving the stability and compatibility of the probes and the workpiece, good coupling effect and detection effect were obtained. The use of a site user shows the correctness and practicability of the improved scheme. 