In order to investigate the puffing and dehydration characteristics of maitake (Grifola frondosa) under Pulsed-Microwave Vacuum Puffing (PMVP) conditions, PMVP experiments were conducted. The effect of vacuum pressure (-60±1.5, -70±1.5, or -80±1.5 kPa), microwave power intensity (75, 150, or 225 w/g), the initial moisture content (50±1.0%, 45±1.0%, 40±1.0%, 35±1.0%, or 30±1.0%) and pulse ratio1.2 on dehydration rate, expansion ratio and sensory score were determined. Moreover, a mathematical model and correlation coefficients for the dehydration rate and expansion ratio of maitake mushrooms with moisture content was established for three microwave intensities. Puffing of samples showed that the microstructures of the maitake slices quickly formed a porous structure during the volume expansion stage and the hardness increased then suddenly decreased. These results are useful for the industrial scale production of high-quality maitake products.