According to the basic principles of thermal stress, experiments and analysis were carried out on the changos of thermal and moisture stress and damage caused by the variation of thermal and moisture environment in the bamboo reinforced concrete. The results show that the coefficient of traverse thermal and moisture expansion is greater than the longitudinal coefficient in the bamboo, and also greater than the expansion coefficient of the concrete. When the pressure stress in the bamboo reinforcement caused by the concurrent enlargement of thermal and moisture exceeds the compression strength of bamboo, damage will be generated inside the bamboo reinforcement, and the compression strength will be brought down. When the tensile stress in the bamboo reinforcement caused by the concurrent decrease is larger than the surface binding stress between the bamboo reinforcement and the concrete, the function of reinforcing rib in the frame will be weakened. The fall of temperature and moisture is one of the most important reasons leading to the damage of bamboo reinforced concrete during the designed operation condition.