The present invention provides oil field well plugging apparatus including ring casing, top cover, sealing block capable of moving radially between the casing and the top cover, lead screw as pull rodconnected outside the sealing block, adjusting part on the lead screw and driving disc outside the adjusting part. Several adjusting assemblies comprising sealing block, lead screw and adjusting partare distributed in the driving disc circumference and connected through the adjusting part to the driving disc. The structure has adjustable sealing diameter for sealing oil string of different sizesto facilitate oil well operation, and has the advantages of sync adjustment, simple structure, flexible use, relaxed machining precision, low making cost, less faults, etc.