To achieve ultrasonic phased array non-destructive testing of internal defects in rocks, complete defect location and grouting effect evaluation, combining ultrasonic phased array theory, first wave amplitude point location theory and finite element numerical simulation method, a numerical model containing internal hole defects was constructed. The take-off time of ultrasonic wave velocity and the characteristics of ultrasonic sound pressure under different aperture conditions were studied. A defect location method and reconstruction model based on ultrasonic phased array grouting body were proposed for the first time, which made up for the deficiency of phased ultrasonic waves in rock defect location. The results show as follows. When the position of the hole defect remains unchanged, the defect echo remains unchanged, and the larger the hole diameter, the greater the sound velocity and sound pressure amplitude of the sound wave. The relative errors of the defect’s lateral and longitudinal positioning are both less than 5%. The bottom echo can effectively verify the positioning method. The shape reconstruction similarity rate can effectively quantitatively evaluate the defect shape reconstruction.