Ultrasonic phased array full focusing method is an imaging algorithm based on full matrix data. It exhibits advantages of high imaging accuracy and great defect characterization ability, while there are some disadvantages, such as large amount of data, long computation time and large nearsurface noise. At present it is mainly used in postprocessing imaging. A correction model based on the angular directivity function is established, and an accelerating algorithm based on triangular matrix data capture and data index technology is designed, combining with parallel computing device. It is tested on an aluminum block with artificial holes with a 16element phased array probe. The result shows that time consumption of each image is decreased to less than 135 ms with the accelerating algorithm, which can be deemed realtime. The correction model is helpful to decrease nearsurface noise, reduce false defects, and improve signal to noise ratio of the image.