Abstract: Magnesite, as a very important mineral in Liaoning Province, is concentrated in the Liaoning-Jilin rift and characterized by large scale, distinct geochemical characteristics features and anomalies and good metallogenic conditions. Based on the favorable geological conditions, the author makes full use of various geological and geochemical prospecting indicators and prospecting probability-geochemical block method to make mineral prediction and evaluation of magnesite in the Liaoning-Jilin rift, divides geochemical block of magnesite and presents geochemical block pedigree with the theoretical basis of geochemical block, and finally delineates 11 prospective areas, including 2 grade Ⅰ, 7 grade Ⅱ and 3 grade Ⅲ prospects, with predicted resources of 11.41268 billion tons.