Plant 3D information is an important parameter in the process of plant growth, reflecting the normal growth state of plants. In order to quickly and nondestructively acquire the 3D information of corn plants, a 3D information acquisition system based on mobile robot platform was designed. The fourwheeldrive robot was equipped with a lifting platform and Xtion camera at the end, and the Xtion camera acquired a 3D point cloud at multiple angles through the motion control of the robot. Firstly, the hardware structure and software platform of the acquisition system were described. Then, the steering of the fourwheel drive robot simplified the kinematics analysis. According to the system collection needs, the fourwheeled robot and the lifting platform controlled the camera to make a circular motion with a radius of R. The camera collected a 3D point cloud at interval of θ until the robot was moved for one circular motion. Finally, according to the transformation matrix 〖WTHX〗T〖WTBZ〗 for calculating the point cloud of the adjacent angle, the registration and splicing of the 3D point cloud were performed, and the filter was used for filtering to complete the 3D reconstruction of the corn. The watershed algorithm was used to mesh and segment the reconstructed maize plants, and the leaf length parameters were measured. The results showed that the motion error for mobile robots was less than 1cm. The error between predicted value and the true value of the leaf length of corn plant was between 1% and 5%. The system provided a new way for the collection of 3D information of corn plants.