Abstract: To solve a series of problems existed in pigging of natural gas pipeline, due to the too fast running velocity or unstable running of pig, research on velocity control of pig is made.Combined with pigging principle of pig,velocity control scenario of pig is presented.Structure design of velocity-controllable pig is carried out, which consists of ordinary pig, electricity chamber, information wheel, motor chamber, DC servo motor, rotary valve, by-pass motor casing chamber etc.Pigging process of the pig is analyzed.It is considered that running velocity of the pig can be controlled within the predetermined scope.However, technical issues need to probe thoroughly in mechanical structure optimization, by-pass hole calculation as well as numerical simulation on compressible fluid when pig is running.