In this paper, we have developed model of cotton organs using NURBS surface, present a introduction of Topological Structures oil virtual plant from Our personal perspective and simulated a 3-D growing of cotton with OpenGL and VC++ 6.0.briefly introduce method of simulating cotton organ based on NURBS and from Our personal perspective present a introduction of Topological Structures on virtual plant. Based on VC++6.0 and OpenGl, methods of establishing models of main cotton organ using techniques of Computer graphics are presented and realistic results have been achieved. Burls of stem and fruitbranches are simulated by octahedronlike prism. Other ogans are built based on NURBS These organs are : bell square caulis leaf square fruit branch leaf square Petal bract. Using NURBS we don't need to obtain an abundance of accurate data and bother with regression equation by contrast with three-dimensional digital. Topological Structures of cotton is represented by C++ class: stein class and fruitbranch class.