Abstract: The fourth generation fighters have the feature of stealth, supersonic and maneuvering, and detection performance of the fighters with traditional radar is bad. Considering the metric-band phased array radar, and using its feature of anti-stealth and agile beam forming ability, a novel long term coherent integration detection algorithm of the fourth generation fighters is proposed. First the modified Keystone transform is used to correct the range cell migration, and then each range cell data is transformed to the time-frequency plane, and Sandglass transform is used to solve the coupling effect between the delay and slow time of the bilinear transformation. Finally, the two dimensional FFT is performed to complete the long term coherent integration and target detection, and the effectiveness of the algorithm is verified by Monte Carlo simulation. At the same time, the algorithm does not need to search, and can be realized by high efficient operation.