Abstract: Due to increasing oil well depths as required,and hence worsening working conditions,standard A PI threaded joints can hardly meet the need for oil fields,whereas newlydeveloped premium threaded-joints are being used more and more widely.Described here are several typical PJs developed overseas,including their design characteristics.Considering the great potential market of PJ,and the domestic industry's failure to produce such product commercially,it is a must to speed up PJ development,aiming at both local and world markets.