Abstract: Deviations of ovality, perpendicularity and partial concave-convex on large-scaled storage tanks are inevitably in construction. Such factors as medium, climate, temperature and tank foundation settlement during the operation of storage tanks will cause changes in geometric shape and dimension of storage tank's floating roof, thus affect sealing result of floating roof tanks. Roller skeleton seal applies several seal skeletons in circular arc line section and make the seal skeleton a chain by means of rotating shift joint and changeable with the tank shape changed under an action of spring force. There equip with rollers at each end of skeleton and they will travel along the tank wall as the floating roof moves up and down, and maintain the distance between the seal skeleton and tank wall. With the functions of rainproof, paraffin scraping and dual-seal, the device has strong economical and practical value.