As an enterprise HRM (Human Resources Management), how to realize the scientific and rational management of the enterprise with the help of BD (big data) technology, and how to mine the information that is beneficial to the decision-making of the enterprise from a large amount of data has become an important issue at present. This paper studies and designs HR (Human Resources) performance appraisal system with BD technology. The advanced nature, maintainability and expansibility of the system should be considered as much as possible in the design. This system adopts B/S structure and ASP.NET three-tier architecture mode. Aiming at a large number of uncertain management factors in HRM, this paper puts forward an HR information management model based on DT (Decision Tree) algorithm. Aiming at the shortcomings that the logical expression of ID3 algorithm is not clear enough and easy to understand, this paper puts forward a new idea of building a tree. In the process of tree building, when the proportion of objects in the subset belonging to the same class exceeds a certain probability, the growth of the tree is stopped, and the node is marked as a leaf node of most classes. After system testing, the correctness of the target system is verified.