In the paper, with the high-sulfur bituminous coal from Chongqing Songzao(St 1.62, Sp 0.94, Ss 0.11, So 0.57) as the research object, a desulfurization test was conducted with microwave combined with NaOH solution to study the effects of various factors on the results of coal desulfurization and the proximate analysis index. The test results show that increasing the microwave power and the irradiation time can reduce the content of the total sulphur in clean coal and improve the desulphurization rate, but excessive increase is useless; the additive amount of the NaOH solution also has an optimum value. The content of total sulfur in the desulfurated clean coal falls to around 0.80%, the content of organic sulfur is around 0.40%, and the content of the pyritic sulphur falls to around 0.18% under the best conditions (microwave power 1000W, irradiation time 5 min, solid-to-liquid ratio 1:4, concentration of NaOH solution 300 g/L). The ash content and volatile content of the desulfurated clean coal also change while desulfurization.