Abstract: The chimney of South Sichuan Gas Mine Purification Factory is a steel chimney lined with refractory bricks.In long-term use process,as exhaust surviving sulfur and other corrosive matters it has serious corrosion and aging.It can not meet the simple reproduction and expansion reproduction need.Which needs reinforcement measures immediately.According to the specific corrosive defects at this chimney,a reliability assessment is done.Through massive computer simulation and finite element computation of residual strength the chimney weak link is got and a comparative analysis of a few reinforcement plans is carried out.Finally reliable plan is obtained so that remarkable economic and social benefits are achieved.