The stability problem of linear systems with time-varying delays is studied by improving a Lyapunov-Krasovskii functional (LKF). Based on the newly developed LKF, a less conservative stability criterion than some previous ones is derived. Firstly, to avoid introducing the terms with h 2 (t), which are not convenient to directly use the convexity of linear matrix inequality (LMI), the type of integral terms { t sẋ (u) du, s t-hẋ (u) du} is used in the LKF instead of { t s x(u) du, s t-h x(u) du}. Secondly, two couples of integral terms { t sẋ (u) du, s t-h(t)ẋ (u) du}, and { t-h(t) sẋ (u) du, s t-hẋ (u) du} are supplemented in the integral functionals t t-h(t)ẋ (u) du and t-h(t) t-hẋ (u) du, respectively, so that the time delay, its derivative, and information between them can be fully utilized. Thirdly, the LKF is further augmented by two delay-dependent non-integral items. Finally, three numerical examples are presented under two different delay sets, to show the effectiveness of the proposed approach.