In this paper, a new scheme of arbitrary high order accuracy in both space and time is proposed to solve hyperbolic conservative laws. Based on the idea of °ux vector splitting(FVS) scheme, we split all the space and time derivatives in the Taylor expansion of the numerical °ux into two parts: one part with positive eigenvalues, another part with negative eigenvalues. According to a Lax-Wendro® procedure, all the time derivatives are then replaced by space derivatives. And the space derivatives is calculated by WENO reconstruction polynomial. One of the most important advantages of this new scheme is easy to implement.In addition, it should be pointed out, the procedure of calculating the space and time derivatives in numerical °ux can be used as a building block to extend the current ¯rst order schemes to very high order accuracy in both space and time. Numerous numerical tests for linear and nonlinear hyperbolic conservative laws demonstrate that new scheme is robust and can be high order accuracy in both space and time.