Digital forestry platform was introduced and special requirements of spatial data discovery were analyzed in this platform. The hierarchical and distributed architecture of spatial data discovery was put forward. Global metadata model, OLAP-oriented metadata aggregation and spatial relation knowledge repository were deeply researched. Global metadata model not only mainly provides spatial data entity description and Web service information but also builds relationship between them; OLAP-oriented metadata aggregation generates date cube through extracting and aggregating; spatial relation knowledge repository supplies necessary knowledge of spatial information process and analysis. Based on aforementioned technologies and researches, spatial data discovery module has realized multi-perspective view data and service display, data and service automatic match and on-demand data service. Thus, it meets special application system requirements on digital forestry platform.