Abstract: A NaCl solution sandwiched by two parallel silicon nanochannels is simulated by molecular dynamic simulation.Compared with silicon walls charged with same charges,when silicon walls charged with different charges,Water concentration is similar,while ion concentration and potential is different.Na+ ions and Cl-ions assemble two sides of nanochannel separately,and in the middle of nanochannel charge inversion occurs;The value of water velocity in the lower nanochannel is negative and positive in the upper;The value of potential is clearly different across the nanochannl,Potential is distributed in exponential curve near the nanochannle walls,The value of potential in the lower nanochannel wall is positive and negative in the upper,while in the lower nanochannel,potential is negative and positive in the upper.By molecular dynamic simulation,it is found that velocity pattern alters when the surface charge in the nanochannel walls is different.