Concept and key characteristics of virtual prototyping technology were described and design principle of small-sized agricultural loader was discussed in the paper. Furthermore, virtual prototype of agricultural loader based on SolidWorks was analyzed, including its three-dimensional modeling, virtual assembly, image rendering, kinematic simulation, interference detection and two-dimensional engineering-drawing conversion. And real agricultural loader image was also shown. The result shows that development efficiency and quality of small-sized loader increased with virtual prototyping technology.