Abstract: In order to solve old down-hole choke problems in Sulige gas field including difficult fishing, short working life, high failure rate problem of the launch for a period of time to open for wells, HY-4 choke is developed. The choke designs a new throttling structure by using the pistons that provide larger force, overcoming the high failure rate problem of the launch for a period of time to open for wells. Its Un-ban structure uses slip to deblock, providing seal space that greatly reduces the inner tube with wells so as to solve the difficult problem of implement fishing. The throttle flap uses artificial ceramic materials to prolong its life. These chokes have been tested in 34 gas wells and the result is proved to be good.