The tangential strains of bamboo in the process of heating and cooling were investigated through dynamic resistance strain gauge. Test results showed that the change of the tangential strain of bamboo with temperature presented mainly parabolic curve form, positive strains gradually increased below 80 ℃，and then decreased gradually，changed into negative strain after 120 ℃ in the process of heating. In the process of cooling the negative tangential strain of bamboo increased slowly from 150 ℃ to 100 ℃，and then rapidly increased from 100 ℃ to 30 ℃. In the process of heating and cooling the tangential strain of each piece was obviously different at the same temperature. The strain presented in the process of heating and cooling would increase the surface roughness degree of bamboo.