Abstract: This paper presents systematically the safety assessment method for in servic e pipelines.The nonlinear finite element method is established to simulate the burst failure of a p ipe containing the various kinds of corrosive defects.The curve diagram which can reflect the relationship among defect depth, internal pressure, maximum stress in defect and pipe materi als performance parameters is set up and it can be conveniently used by the technicians in the field.In order to consider the comp lexity and uncertainty of many factors concerning with pipeline safety, the reliability-based assessment t heory and method are presented.It can compute the failure probability along the total length of pipe lines according to corrosion inspection data and represent completely the safety status of the pipeline.In p rediction of the remaining life of the pipeline, the probabilistic mathematical model is presented based on the corrosive rates to predict the failure probability.The software system developed embodies safety assessment da tabase, corrosion analysis, pressure distribution analysis, residual strength assessment, remaining lif e prediction and maintenance decision making in the whole body.It can effectively analyze and evaluate the safety status in different operation stages.It aids carrying out scientific dynamic management to the pipe line.It has a reasonable system design.Users can use it easily.