Bamboo-wood composites laminated veneer lumber (LVL) was treated under different temperature and humidity conditions. The mechanical properties of bamboo-wood composites LVL after the treatment were discussed. The results showed: (1) After the treatment of high temperature and humidity, all the mechanical properties of the LVL decreased obviously, in which, MOE decreased 30.70% in average, MOR decreased 38.3% in average, toughness decreased 11.7% in average. (2) After the treatment of low temperature, the MOE and MOR of bamboo-wood composites LVL revealed the trends of slight increase, the average increase rate of MOE was 2.5%, the average increase rate of MOR was 5.4%, the average decrease rate of toughness was 37.9%. (3) During the treatment of fluctuation from high temperature to low temperature, the MOE and MOR of bamboo-wood composites LVL were in the state of fluctuation, the increase rate or decrease rate of MOE was less than 5%, the increase rate or decrease rate of MOR was less than 10%, toughness displayed the trend of decrease, the decrease rate was 18.7% in average.