Smoothed Particle Hydrodynamics(SPH)is a Lagrangian meshless particle method.However,its low accuracy of kernel approximation when particles are distributed disorderly or located near the boundary is an obstacle standing in the way of its wide application.Adopting the Taylor series expansion method and solving the integral equation matrix,the second order kernel approximation method can be obtained,namely K2_SPH,which is discussed in this paper.This method is similar to the Finite Particle Method.With the improvement of kernel approximation,some numerical techniques should be adopted for different types of boundaries,such as a free surface boundary and solid boundary,which are two key numerical techniques of K2_SPH for water wave simulation.This paper gives some numerical results of two dimensional water wave simulations involving standing wave and sloshing tank problems by using K2_SPH.From the comparison of simulation results,the K2 SPH method is more reliable than standard SPH.