A petiole modeling method based on keeping original data constant technology was presented. The length and radius parameters were set to establish a 3-D model, and the surface hair simulation was used to enhance the sense of reality. In order to produce 3-D models with multiple shapes, an interactive method was proposed to adjust the model shape based on joint chain, IK method and error compensation algorithm which made the method could keep the original parameters (length and radius) constant. The results showed that the method could build 3-D petiole model quickly and flexibly, and had good realistic effect. More importantly, the variation of parameters was very small in the interactive deformation process. 