The paper is to study the number, morphology and ultrastructure of fibroblasts in the process of wound healing of local irradiated rats. 156 Wistar rats were divided into two groups, the wound group (control) and the radiation-combined wound group (radiation group). Numeral, morphological and ultrastructural changes of the fibroblasts were observed with light microscope and transmission electron microscope. The α-SM actin expression in the fibroblasts was measured with immunohistochemecal assay. The number of the fibroblasts in the control group increased gradually and reached to the max on the 10,th, day. In the radiation group, the fibroblasts number changed less than the control and the peak was seen on the 15,th, day. The fibroblasts included types of the transition, the proliferation, the synthesis-secretion, the myofibroblast, the transformation and the apoptosis. For the radiation group, each of the six types of fibroblasts, especially the synthesis-secretion type and the myofibroblast type, appeared later in comparison with the control. In addition, the peculiarities of the abnormal fibroblasts could be observed in the radiation group, the highly expanded rough endoplastmic reticulums, the less golgis and microfilaments. Irradiation can inhibit the proliferation of the fibroblasts, delay the appearance of the stage-specific fibroblasts, cause the morphological and ultrastructural changes in the fibroblasts and promote the formation of the abnormal fibroblasts.