A large number of data have been accumulated in our country during the long-term investigation and statistics of forestry resources, and it has become key problem to find out the relationship of the environment and forest growth from the large number of existing forestry resources data. In this paper, the data mining technology is used in planning and design of forestry resource, and the process of data mining is studied, considering data mining and design process of forestry resource decision, we firstly study data mining technology, then collect the data and perform data processing, select the algorithm of data mining, and establish Bayesian evaluation model, then explain and analyze the decision analysis of forestry results. Practice has proved that data mining methods have improved the accuracy and reliability of decision making of forestry management, and provided new theory, methods and technology for research of growth management of forestry.