A series of radio frequency/vacuum （RF/V） drying tests were conducted on boxed-heart timbers of plantation larch. Various RF/V conditions were analyzed to optimize the drying quality and drying speed. We found that the optimized RF/V parameters were: 0.4 A input current,2 kV electrode voltage,50 ℃ temperature,3 minutes oscillation circle then 1 minute for stopping;and 13.33 kPa vacuum pressure at the early drying stage and 6.67 kPa at the final stage.