Crop organ morphological model is one of the key technologies of virual crop. By observing and analyzing the morphological and topological structures of wheat spike, the morphological parameter-based 3D geometric model and visualization method were developed. Based on the existing morphological model of spike in wheat, the 3D morphological geometric model of wheat spike was constructed by integrating the topological structure of spike, including the submodels of ear axis, spikelet (including outer bran, awn and anther) and spike shape. The ear axis was constructed by connected proglottids which were represented by slant cylinder. Based on the surface vertical curve, the outer bran was simulated by approximate semiellipsoid with triangular faces. The awn, with transversal surface as nearly equilateral triangular, was constructed by triangular faces based on the curve of awn. The anther on the top of floret in flowering stage was simulated with NURBS surface. In addition, the spike shape was controlled by using hierarchical model. Then according to the topological structure, the above organ models were organized together to rebuild the whole 3D geometric model of wheat spike. By further integrating the rendering models of color, texture and light, the visualization of growth dynamic of wheat spike was realized based on the platform of Microsoft .Net and CSOpenGL graphic library. The reconstructed geometric model with three dimensions can simulate visualization of growth dynamic of wheat spike under different varieties and treatments. The result will be helpful to realizing the realistic simulation of wheat plant, and the digitalization and visualization of growth dynamic of wheat.