This study shows the effects of catalyst, temperature and time of heat treatment on the weight percent gain (WPG) of Neolamarckia cadamba and Canarium album Lour. Raeusch woods. The results showed that the high WPG of Neolamarckia cadamba treated by mDMDHEU was obtained by using MgC12.6H20 catalyst at 3 percent (compared with amount of mDMDHEU chemical), temperature treatment 100°C for 12-16 hours (WPG from 37.55 percent to 40.45 percent) or at temperature .of 120°C for 8 hours (WPG achieved 39.58 percent). When Neolamarckia cadambawas treated by mDMDHEU with MgC12.6H20 catalyst of 11 percent, at temperature treatment at 80°C for 16 hours, WPG achieved 39.43 percent. The treated Canarium album Lour. Raeusch wood by mDMDHEU has high WPG with MgC12.6H20 catalyst at 3 percent, temperature treatment 100°C for 12 hours (wpG achieved 27.61 percent) or at temperature of 120°C for 8 hours (wpG achieved 28.72 percent). For Canarium album Lour. Raeusch, it'd better not using catalytic rate of 7 percent, 11 percent due to the WPG obtained much lower than the catalyst rate of 3 percent. For the same treatment parameters, WPG of Neolamarckia cadamba is higher than that of Canarium album Lour. Raeusch.