The improvement of synthetic aperture radar (SAR) imaging resolution brings new challenges to SAR high-precise and real-time imaging processing. Selecting efficient imaging algorithm and utilizing hardware platform for algorithm acceleration are two effective methods to solve the problem. A new efficient and precise imaging algorithm is proposed for the ultra-high resolution airborne SAR. Parallel hardware platform GPU is utilized to accelerate the algorithm. The processing results of the SAR measured data fully verify the accuracy and efficiency of the new imaging algorithm.