The algorithm of Gravity matching is one of the key technologies in realizing the gravity aided the inertial navigation. However, the defects of the traditional gravity matching method being high in complexity and narrow in application scope, it is difficult to achieve accurate and fast matching effect. Under the certain condition of abnormal accuracy, the use of the improved ant colony optimization algorithm in the process of gravity matching can reduce the mismatch rate in putting the velocity information provided by Doppler speedometer as constraints. The results of simulation show that the algorithm is high in matching rate, and can achieve precise and fast matching location, realizing the gravity aided navigation.