The use of oil palm biomass other than the palm oil leads to increased efficiency as more energy is obtained from oil palm plantations. For each kg of palm oil, roughly another 4 kg of dry biomass are produced, approximately a third of which is found in fresh fruit brunch (t•13) derived wastes, while the other two thirds is represented by trunk and frond material. This problem might be a contribution to increment of wastes production. One of the alternatives ways is to utilize the oil palm biomass by producing particleboard from oil palm trunk particles. For this study, it was conducted to focus on the effect of pressing time and the properties of particleboard made using glutardialdehyde treated oil palm particle. The different pressing time used in this experiment was 10, 15 and 20 minutes. The method includes sample collection of oil palm trunk, raw material preparation by using spray mixing technique, woodchip treatment by using 25 % concentration of glutardialdehyde, composites making and composites evaluation. Composites evaluation includes density test, moisture content test, thickness swelling and water absorption test and also bending test. From the result obtained, the most suitable pressing time used was 15 minutes with value of 0.45 g/cm3 for density test, 6.63 % of moisture content, 16.17 % and 19.48 % of thickness swelling for 2 hours and 24 hours respectively. The value for 2 hours and 24 hours water absorption are 142.83 % and 145.25 % respectively. 15 minutes pressing time particleboard also showed the highest value of MOR and MOE with value 2.61 lslimm2 and 390.48 Islimm2 for each.