The steam gasification experiment of FJC lignite, BL lignite, SH bituminous and TT anthracite were carried out by using an own design WFSM-3060TL Catalyst Evaluation Unit apparatus. The infulence of coal rank on the steam gasification activity was investigated. Experiment conditions: heating rate:15°C/min (25°C-500°C), 2°C/min (500°C-850°C). The resuts show that gasification of lignite is better. With the deepening of coal rank, the steam gasifiction reactivity of coal samples decreases obviously, the higher the coal rank is, the worse the gasification reactivity is.