Abstract: In order to improve the processing effects of microwave loosening machine,the microwave chamber of the machine was divided into three sections,namely the first section(input end),the second section(intermediate zone),and the third section(output end).The effects of processing parameters of each section on blended tobacco were analyzed with orthogonal experiment,extreme difference analysis and variance analysis,the results showed that:1) within the test range,the optimal microwave powers of magnetrons in the 1st,2nd,and 3rd sections were 14,15 and 16 kW respectively,the optimal microwave processing time was 330 seconds;2) with the optimized parameters,the loosening rate of tobacco increased by 0.21%,the mean temperature and temperature difference between tobacco layers reduced by 1.4℃ and 2.3℃ respectively,and tobacco breakage reduced by 0.17% after processing.