The performance of the integer-ambiguity decorrelation algorithm in the Global Navigation Satellite System (GNSS) directly affects the accuracy and the efficiency of the solution of integer ambiguity.In order to improve the efficiency of the integer-ambiguity decorrelation algorithm, a method was proposed to organize the diagonal elements of the ambiguity covariance matrix in ascending order at first, then reorganize the diagonal elements of the transformation matrix in descending one, thus to improve the termination conditions of the existing algorithm, and improve the effect of decorrelation solution and the ambiguity search efficiency.The numerical simulation results show that, compared with the decorrelation algorithm based on diagonal ascending order and the iterative algorithm, the algorithm proposed here has obvious advantages on decorrelation performance in high-dimensional data space, which is suitable for the integer ambiguity solution of multi-satellite navigation system.