Abstract: The height of fracturing fractures is one of the essential parameters in the evaluation of fracturing effect.Due to the restrictions such as long period of operation and high risk of radioactive pollution,conventional ways of evaluating fracturing fractures,borehole temperature and isotope logging,cannot be applied for offshore oil field.On the basis of assessing the risk of cross strata,a method combining casing cross dipole acoustic and cementing quality logging(SBT)is proposed to precisely evaluate the height of fracturing fractures.The height of fracturing fractures provided by this method are proved to be precise enough to guide the fracturing operations in several offshore wells,which demonstrates the method is worth applying widespread.