The invention discloses a pile foundation defect detection and repair method for a cast-in-situ bored pile. The method comprises the key steps that when a heating element (5) is located at a certain depth, if the waveform peak value of only one thermal inductance optical fiber (4) declines, it is judged that a cavity is formed in a pile body (1) at the depth, and the cavity is located at the position, passing through the radius of the abnormal thermal inductance optical fiber (4), of the cross section of the pile body (1); when the heating element (5) is located at a certain depth, if the waveform peak values of two adjacent thermal inductance optical fibers (4) decline, it is judged that the cavity is formed in the pile body (1) at the depth, and the cavity is located on a sector face formed by two radii passing through the two abnormal thermal inductance optical fibers (4); when the heating element (5) is located at a certain depth, if the waveform peak values of all thermal inductance optical fibers (4) decline, then it is judged that pile breaking exists at the depth. By means of the method, no missing detection is caused, the longitudinal depth of a broken pile at each layer can be detected accurately, the longitudinal depth of each cavity and the transverse locations, located on the cross section of a pile foundation, of the cavities can be detected, and effective repair can further be conducted on each defect.