This paper is concerned with the delay-dependent stability and robust stability of linear uncertain system with interval time-varying delay. By splitting the delay-interval into two segments of equal length, some new types of Lyapunov functional are constructed for each segment. Based on convex combination technique, several improved delay-dependent stability criteria are derived in terms of linear matrix inequality. The proposed method involves neither model transformation nor any free weighting matrix, so it can reduce the complexity in computational demand. Numerical examples are given to demonstrate the effectiveness of the proposed method.