| For more accurately capturing complex flows, a new fifth-order WENO scheme is developed by improving the smoothing factor of WENO scheme. Weighting the third-order ENO scheme can obtain a fifth-order WENO scheme, but with different weighting methods, the WENO scheme will have different effects of maintaining weighted essentially non-oscillatory schemes at extreme values. In this paper, the local smoothing factor of second-order accuracy and the high-order global smoothing factor without first-order, second-order derivative are constructed, so that the WENO scheme has fifth-order accuracy at the extreme value. Based on the improved fifth-order WENO scheme, the classical problems of one-dimensional convection equations, one-dimensional and two-dimensional Euler equations are verified by examples, and compared with the traditional WENO-JS scheme and WENO-Z scheme. The calculation results show that the improved fifth-order WENO scheme has higher accuracy and convergence speed, and can effectively capture complex flows such as discontinuities, shock waves and eddies with low dissipation.