Abstract: in order to improve the slurry concentration of te lignte,the paper considered the two factors of the microwave output power and the microwave iradiaton time afifcted to the suory biliy of the lgnte. Three difrent output powers and thee difrent microwave iradiaion times were seleced to treat Mengdong lignte.After the microwave radiaton.the coal samples and raw coal would be applied toprepare the coal water suory Wih the appicaion of the static nitrogen adsorberan anaysis was conducted on the pore size stouctures of the raw coal sample with different power mictowave radiation.The chemia ltiraton method was aplie to measu Ethe number of the oxygen functional groups and to study the mechanismo of the microwave rradiation to improve the sur biliy of lignte.The resuts showe that witthe microwave iradiation power increased and the iradiation time expanded.,the moisture content of the ligntie would be rapily decreased.the number of oxygen fnctonal grous would be redced and the porestricture oflignte would be improved. The max sury concentraton of the lignite was improved fromn 50.16% to 53.44% andthe flowability of slurry would be obviously improved.