Canada Poplar （Populus canadensis） and Manchurian Ash （Fraxinus mandshurica） wood were modified by microwave heating for various treating times. They were then dried together with similar untreated wood under the same drying conditions. Experimental results were based on electron microscope scans as well as data collected on drying speed and shrinkage measurements from modified and unmodified wood. The results showed, 1) some pit membranes of the treated wood were destroyed and some tylose were redistributed, or separated out after the microwave modification process, 2) the modified wood revealed better properties than the unmodified wood, especially the hardwood. The treated wood was found to have lower density, a larger shrinkage ratio, a higher water absorbing characteristic and a faster drying speed.