The invention relates to a pipeline flexible 
crawling robot which comprises a forward walking mechanism, a 
backward walking mechanism and a steering mechanism, wherein the steering mechanism is arranged between the forward and 
backward walking mechanisms; each of the forward and 
backward walking mechanisms comprises an engine base, a primary motor, a secondary motor, a worm, a support disc, a 
leadscrew, a nut, a spring, a sliding sleeve, a baffle ring, a guide rod, a swinging arm component and a connecting rod; the swinging arm component comprises an arm rest, a chain, a worm gear set and a gear set. The primary motor drives the gear set to rotate through 
worm drive and chain 
wheel drive; the secondary motor flexibly drives a gear of the swing arm component to radially support or leave the inner wall of the pipeline through a screw drive pair composed of the nut and the lead screw, the spring, the sliding sleeve and the connecting rod; the steering mechanism comprises a motor, a 
cam,a driving lever, a support plate, a main spring and a connecting piece; the connecting piece passes through the 
cam and the support plate and then is connected with the forward and backward walking mechanisms. While the 
cam and the driving lever push / pull the connecting piece, the motor forces the forward and backward walking mechanisms to deflect mutually. The pipeline flexible 
crawling robot provided by the invention has the advantages of simple structure and great 
tractive force and can crawl and turn along the inner wall of the pipeline.