Catalytic gasification characteristics of coal using Na2CO3 as a catalyst were studied in thermogravimetric analyzer(TGA) and in situ heating stage, respectively. The effects of gasification temperature (650–900°C) and catalyst loading amounts (10,15 wt %) on the associated gasification process were investigated. Interactions of Na2CO3 with carbon at gasification phases were observed by an in situ heating stage microscope. The results show that the interactions of Na2CO3 with coal at gasification phase varied with reaction temperature and the morphology structure of carbonaceous materials. Two different gasification reaction forms were observed for Shenfu (SF) and Zunyi (ZY) acid-washed char samples mixed with Na2CO3. For the SF-acid-0.15Na-800P sample, the Na2CO3 liquid film might flow and enter the inner space of SF-acid-0.15Na-800P at or above the melting point of Na2CO3, while with the consumption of carbon continuously, the internal Na2CO3 liquid film gradually exposed and spread outward. While ZY-ac...