The paper presents an improved algorithm based on suffix array for string matching. In paper, by utilizing a generalized algorithm, called DC3, that allows a space-efficient implementation and, moreover, supports the choice of a space-time tradeoff, we get the suffix array in linear time. Meanwhile, in order to reduce matching time, the new algorithm improves the search conditions in the process of accurate string matching and filters the suffix strings which do not meet the conditions to reduce the times of the character comparison. Comparing the improved algorithm with the original one, the experiment results show that the new algorithm saves query time and increases matching efficiency on the condition of increasing space complexity properly.