The invention discloses a method for optimizing a tension system for rolling of an ultra thin steel strip of a cold continuous rolling mill, and relates to control equipment or method special for metal rolling mills or machining products of the metal rolling mills, in particular to optimization of a comprehensively-controlled tension system in the rolling process of ultra thin materials of the cold continuous rolling mill. The cold continuous rolling mill is used for controlling existing equipment parameter and technological parameter data of equipment; according to inlet tensile stress, outlet tensile stress, deformation resistance, the rolling speed, the width of a strip material, the inlet thickness, the output thickness and the working roller diameter of all racks, slipping factors, hot slip indexes, vibration coefficients, rolling force and rolling power of all the racks under the current working condition are calculated; through program control of a computer, optimization control over the tension system is achieved; the depressing capacity, the rolling efficiency and outlet strip shapes and tensile stress distribution of all the racks are considered while the rolling stability, slippage, heat slippage and vibration are considered; and the tail rack output strip shape which represents the strip quality is obviously reduced, and the strip quality is obviously improved than that of a traditional method.