The circulation caused by surface heating in a valley formed by two bell-shaped hills has been simulation in a water tank with PIV (Particle Image Visualization) method. The surface heating is used of a copper plate with electricity. The flow fields have been simulated in the quiet water under three fluid stratifications, such as in the neutral, in the stable and with an inversion layer in the half height of the hill. Results obtained are as following. (1) Under the neutral condition in the water tank, the circulation caused by the surface heating in a valley can be stretched to the part above the top of the hill. A big vortex is formed in the valley. (2) Under the stratification with an inversion layer in the half height of the hill, the vortex caused by the surface heating is imprisoned below the inversion layer. The vortex could not develop to the inversion layer. (3) Under the stable stratification, the vortex caused by the surface heating is smaller compared with that under the neutral and with an inversion layer conditions. The vortex developed bloomy is located at the part above the half height of the hill. The conformations of the circulations in a valley caused by the thermal force at different stage have been simulated under the weak winds or at the still air. The results can offer some basis for the observation and numerical simulation of the circulation caused by thermal force.