Provided is a pile integrity detection system based on cross-hole sonic logging method. The operator sets the ultrasonic detector into the measuring tubes of the to-be-detected pile, subsequently inputs the project data and activate the ultrasonic detector, by an acoustic wave transmission among a transmitter and a receiver, a wave energy data of the to-be-detected pile can be obtained, and the wave energy data and a project data will be automatically transmitted to the cloud computing module, thereby the integrity level of the to-be-detected pile can be determined without any manual analysis to the wave energy data, preventing from any error or deflection due to manual operation, whereby it greatly improves the accuracy and efficiency of detection and reduces the error rate.