Abstract: This paper presents a method of modeling cotton organs in three-dimensional images based on NURBS, which realizes the visualization of cottongrowth by using Object-Oriented Programming. To build a NURBS surface, a convenient and accurate method for obtaining 2D(X,Y) coordinates of control points based on cotton imagewas proposed. Solution of 3D organ normalization was discussed. With NURBS thereis no need to obtain an abundance of accurate data and to bother with regression equation as compared with three-dimensional digital method. Burls of stem and fruit branches were modeled by octahedral prism. Other organs were built based onNURBS, such as caulis leaf, fruit branch leaf, bell, petal and bract. Topological structure of cotton is represented by C++ class: stem class and fruit branch class. Based on VC++6.0 and OpenGL, the methodsfor establishing models of main cotton organs using techniques of computer graphics were presented and realistic results were achieved.