Abstract: Problems existing in design, construction and operation of floating roof tanks are introduced, and suggestions presented to solve the problems. In addition to the design of tank body, adequate attention shall be paid as well to the design and selection of tank accessaries, because damage to accessaries tends to infh ence directly normal tank operation. From a long-term point of view, it will pay to upgrade the quality and technical standards for the design of facilities in tank, and to minimize possible leaks in static seals, especially in flange connections. Tank shell deformation due to improper installation will severely reduce paraffin scraping efficiency and damage sealing system. The come off paraffin, in turn, tends to damage the accessaries in floating roof, block the drains, and cause fire in storm weather. Such problems in accessary welding as insufficient weld depth and length, and poor visual quality will cause future safety problems. Proper schedule for tank heating shall be arranged so as to recieve and discharge oil at a temperature above 10℃.