—Temperature and pressure fields distribution during steam flooding through horizontal wells is very important to researches. The present experimental study is conducted to investigate the effect of steam flooding through horizontal injector-horizontal producer when high permeability section exists in the horizontal section and the ratio of permeability is 1:8. And 13 differential pressure transducers with high accuracy are installed in the model to measure the pressure field variation in reservoir during the experiments. And 13 differential temperature thermocouples are put on the model to measure the temperature field variation. Water cut and cumulative oil recovery are obtained. And effects of heterogeneity on temperature and pressure fields are obtained from experiment.