Abstract: In the process of ultrasonic testing of centrifugal spheroidal graphite iron pipe nodularity,as the special shape of the pipe, it was very difficult to set the sound travel and the sound path. Transverse wave velocity method was designed with the special probe device to overcome the influence of the pipe thickness to the tested velocity. According to the tested transverse wave velocity in the centrifugal spheroidal graphite iron pipe,the linear relationship between the nodularity and the ultrasonic transversal wave velocity was obtained at room temperature. The testing results well met with the theoretical analysis.