The development of both elastic and plastic strains of timber surface and internal layers from fast growing plantation wood Populus tomentosa, Pinus massoniana etc. was studied. Results showed that the hardness level of drying schedules had much influence on both the drying strain developed and the time when it reached its maximum value. At the primary stage of drying, the maximum value of elastic tension strain of the timber surface increased with drying temperature rising, and decreased with increment of equilibrium moisture content ( EMC ). If the EMC could be correctly set at the primary stage of drying, the maximum value of the tension strain could be controlled and then good drying quality could be gained.