Abstract: In order to explore the effect of microwave power density on microwave vacuum drying(MVD) of products,based on the experimental analysis of drying characteristics,the dynamics equation of microwave vacuum drying of carrot was simulated numerically,and then the optimization of microwave vacuum drying of multi-power combination of carrot was studied by genetic algorithm. The results showed that the higher the microwave power density was,the higher the drying rate was,the shorter the drying time was and the easier the product was to be burnt. In the comparative study on the numerical fitting of four common thin-layer drying models and their extension models,it was found that the dehydration of carrot slices during microwave vacuum drying under different power could be well represented based on the wang extension model 1(MR=aexp(-ktⁿ) +c). Furthermore,the kinetic equations of carrot drying under three different microwave power densities(20,5 and 0.6 W/g,) were taken as the object. It was verified that the dry base moisture content of carrot slices processed by this process was 0.078±0.005 g/g without coke paste. Compared with the drying results of 0.6 W/g single microwave power,the product not only reduced shrinkage and coking phenomenon,but also improved the drying efficiency by 4.77 times. The application of computer genetic algorithm can optimize the microwave vacuum drying process of multi-power combination,reduce the experimental workload,and obtain the computer numerical simulation model,which can provide technical support for realizing the informatization of microwave drying process.