The illegal use of lands has come to impose a serious threat to land resources protection and land use plan implementation in China. Land use patrolling has long been proven to be an effective means for detection, investigation and prevention of illegal land use. However, land use patrolling performed in the traditional way is laborious and cumbersome. Central and regional government authorities are both seeking high-technology solution to enhance this job. In an effort to satisfy such requirements, we have designed and implemented an integrated system of mobile GIS, D-GPS and wireless Internet to assist land use patrolling and investigation. Details of this system are presented in this paper, including those of the system architecture, the field work-assisting subsystem, the Internet-based D-GPS subsystem ... etc. The main finding is that such technology is indispensable for land use patrolling and similar tasks. It can dramatically promote the patrolling or field work efficiency and tightly connect field and office staff to better perform the mission. Problems encountered in building the system are also discussed.