Hardfill dam is a new type dam. Because its material and construction way are different from general concrete dams, the stress distribution possesses the features in itself. The elasticity modulus and specific creep of the Hardfill material are studied at first, and then, on the basis of the characteristics of material, structure and construction of the dam, a whole simulation procedure is developed by using the finite element method so as to analyse the temperature and stress fields of the Hardfill dam. The research results show that the foundation temperature difference is not a critical factor, and that tensile stresses still exist because of the temperature difference between the surface and inside of the dam. A corresponding improved design scheme is proposed, in which setting surface joints substitutes for penetrating joints to guarantee the anti-fracture safety of the dam surface and decrease the disturbance to dam construction.