An unsteady heat transfer model of cement clinker in a grate cooler was built by according to theory of seepage heat transfer in porous media. Then, the heat transfer law of cement clinker in a grate cooler was obtained by solving the equations of seepage field and temperature field. Using the model, the influence of two main working parameters, grate speed and wind pressure, in the clinker cooling process were analyzed. The calculation results showed that the air temperature and clinker temperature rise with the increase of grate speed and a reasonable grate speed range is 0.007-0.009 m/s. The air temperature and clinker temperature dropped with the increase of air supply pressure and a reasonable air supply pressure range is 6,000-8,000 Pa.