. This paper presents the results of a study that investigated the effect of preservation treatment on ultrasonic velocity, bending strength and compressive strength parallel to grain. Acacia mangium wood which has moderate strength and low-moderate natural durability were used in this study. Retention and penetration of preservative compound on wood as well as ultrasonic velocity and mechanical properties were determined as impact of using three concentrations of waterborne preservatives CCB (chrome, copper, boron) and two preservation methods (cold-dipping and pressure-vacuum). The result showed that pressure-vacuum method significantly reduced ultrasonic velocity, bending strength and compressive strength parallel to grain of wood, but no significance influence on modulus of elasticity (MOE). Meanwhile, concentrations of preservative compounds were no significance effect on those properties except on retention and penetration. Ultrasonic velocity through dynamic MOE had close correlation to predict static MOE and wood strength.