Abstract: In this paper, Moso bamboo is the main object to study its radial compression mechanical properties of bambooculm by ring stiffness method. It was found that the optimum length of samples was its outer diameter. The ring stiffness of Moso bamboo was 80-180 kN/m2, far greater than QB/T 1916-2004 standard given in the SN16 level. Ring stiffness increased with stem height from bottom to top, but declined after 4-year-old. Bamboo joint can improve the radial compression of bamboo-culm，and that with bamboo joint was about 2.30 times of without. Using hose clamps can improve the strain of bambooculm, but the holes reduce its radial compression performance with the increase of hole diameter. Therefore, it is inferred that ring stiffness can be used as a novel and reliable method for assessing the radial compression mechanical properties of bamboo-culm.