Based on the breast anatomical structure and physiological characteristics, a three-dimensional thermal model for normal and embedded tumor breast which considered the metabolic heat generation, blood perfusion and heat exchange between vascular and breast was established. Finite element method was used to solve this model for numerically simulating the temperature distribution of breast, and then the effects of various factors, such as blood perfusion, metabolic heat generation, the size, location and numbers of breast tumor, air convection coefficient and environmental temperature on the temperature distribution of breast were discussed. The results show that the temperature profiles of breast could be significantly affected by the metabolic heat generation, blood perfusion, tumor size, tumor position and numbers, while the surface thermal expression of embedded tumor breast could be influenced by the air flow and environmental temperature. This study results may guide the experiment of breast thermograms and provide important reference for its qualitative analysis.