Land reserving enables the government to control land market easily and reduces the rent-seeking behaviors in the process of assigning the right to the use of the land. The land reserving could move the stock of urban land and improve the land utilization. However, the land reserving projects also belong to investment activities and the amount of investment is huge. In the same time the investment cycle is long. Operation of the land reserve, there is a lot of uncertainty, is likely to lead to investment failure. So, The purpose of this paper is to calculate the value of risks, build forewarning risk control models and judge the fluctuation of risk values in the process of decision-making for multiple land reserve projects and the trend of risks and the center of land reserve preference in decision-making. Integrated methods of documentation, model and case study are employed. The result shows that the forewarning control limits are built based on the reliability series model in a non-repairable system and Shewhart control charts and the time series regression judgment model is built after the limits. It is concluded that through the measurement, forewarning and judgment of time series regression of risk in the land reserving projects of some city, the method is validated.