///Inner Mongolia is a very important coal-resources reserve base in China, where most of the coal seams are accumulated in the Cretaceous faulted basins. The Wujianfang coal basin is rich in coal resources and the total explored reserves of coal is 10.77 billion tons according to the general and detailed survey of coal resources. Based on the coal petrological and chemical analysis of fifty-seven coal samples from three wells in the southeast of the coal basin, the coal quality characteristics, coal facies types and their evolution characteristics are discussed. The results show that the studied coal seams are of low-middle high ash, high volatile matter yields, low-very low sulfur content, and high vitrinite-inertinite ratio (V/I) and tissue preservation index (TPI).