In perspective of evolution processes of the land allocation system,the paper analyzes the forming process of gray land market. Using the data collected of illegal land cases,we study the gray land market situation.The results show that during 1993 and 1996,state unites and collective organizations are the dominating violators.During 1998 and 2002,illegal occupation is the primary illegal behaviors,and illegal attornment is the important component.The ambiguous land property,imbalance in benefits allocation and the dual-track land system are the main causes of forming the gray land market.