As the damages on nonmetallic pipes, especially early damages, are difficult to be detected by ultrasonic guided wave, this paper proposes a nonlinear ultrasonic guided wave with signal delay to detect and localize the defects on nonmetallic pipes. Based on the nonlinear ultrasonic wave theory, the damage states of nonmetallic pipes were analyzed and an incentive method with mixed signals from the same end of the signal delay was developed to generate signal delay according to different speeds of the mixing signals and to implement nonlinear modulation. The instantaneous characteristics of delay signal were extracted by HHT(Hilbert-Huang Transformation), and damage location was achieved by analyzing different nonlinear modulation groups with signal delay. PVC(Polyvinyl chloride) pipes were used for experiments. In intact condition, the standardized reference values of signal delay groups is 0.518 8. In damage of one crack, standardized value of signal delay groups is 0.593 7 and the relative error is 3.277%. Moreover, in damage of two cracks, the standardized value of signal delay groups are 0.593 7 and 0.607 3, and the absolute error is less than 4mm. Compared to the wavelet envelope location approach, the relative error with one crack rises to 36.4%. These results turn out that the approach proposed in this paper is effective and accurate for the damage detection and location of nonmetallic pipes, and is available for the multi-damaged pipes.