With the rapid development of human resource management theory and the increasing improvement of management technology, enterprises choose solutions based on qualitative analysis by experienced experts when making decisions, and the solutions are relatively simple. The disadvantages of this traditional qualitative method are unscientific, imprecise, and costly. Therefore, this article has conducted research on the optimal decision-making of enterprise human resource planning through DM (Data Mining) algorithm. The experimental results show that using this algorithm to design a human resource planning decision support system improves the registration and timeliness of human resource scheduling and allocation, and has good human resource information management capabilities, which has certain application value in human resource information management. By constructing a human resource planning and decision support system, we can classify, store, and schedule human resource information, improve the information distribution and scientific coordination capabilities of human resources, thereby better exerting the initiative of human resources, promoting the development of post construction, and further improving production capacity.