In order to obtain the topographic information efficiently, a tractor-mounted field 3-D topography surveying system was developed. The surveying system consisted of a measuring laser receiver, a GPS receiver, an intelligent controller and a hydraulic system. Furthermore the system could also conduct laser land leveling. The measuring laser receiver was used to obtain the elevation, and the GPS receiver was employed to obtain the longitude and latitude data. Both of them were fused in the controller so as to get the 3-D topographic information. The field experiments were carried out in different moving speeds and then the data measured by the surveying system were compared with the data from the fixed-point surveying method. The results show that the surveying system has a good consistency with the fixed-point surveying method in lower moving speed.