A feasibility study is conducted on the use of piezoelectric ultrasonic method to detect defects in the compactness of fully grouted sleeves, in response to the low practicality of existing on-site testing technology for sleeve compactness. Determine the identification parameters for sleeve damage by analyzing the time-domain and frequency-domain signals of health and defect states through experiments and numerical simulations. There is a significant difference in amplitude between the time-domain signals of defective sleeves and healthy sleeves. In the circumferential detection, the amplitude on the defect side is significantly larger than that on the dense side, and it is found that the peak frequency of the healthy signal is closer to the excitation frequency relative to the defect signal. Define a defect evaluation index based on the difference in received signal amplitude - the difference value. The larger the difference value, the less compact the internal structure of the component. After performing spectral characteristic analysis on the received signal using Fast Fourier Transform (FFT), it was found that there is a significant offset between the peak frequency of the defect signal and the excitation frequency. The experimental results are consistent with the simulation results, verifying the feasibility of the defect recognition method and circumferential detection method proposed above.