Abstract: The fluid-to-solid conjugate heat transfer（CHT） in the rectangular channels with heated plates was simulated with CFX code in this paper,and the analysis of the sensitivity of the mesh to heat transfer was conducted,and a better mesh scale was obtained.Finally,the advantage of fluid-to-solid conjugate heat transfer simulation was analyzed by the comparison with the simulation of direct surface heat flux adding.The results show that by the fluid-to-solid conjugate heat transfer simulation,the weakness of channels can be studied more accurately,and thus to improve the performance of thermal engineering.