In this study, the finite element analysis method was used to study the microwave penetration depth of poplar wood with different moisture content. The influence of microwave frequency and moisture content of poplar on microwave penetration depth was explored. The results showed that when the moisture content of poplar wood increased from 30% to 110%, the penetration depth of microwave with 2.45 GHz decreased from 22.30 cm to 3.64 cm, and the penetration depth microwave with 0.915 GHz decreased from 60.32 cm to 9.85 cm, meanwhile, the internal temperature uniformity of poplar wood became worse...