The wellhead device relates to an oil production wellhead device, which comprises a tee, a gate, a pipe hoop, a short joint, a flange and a polished rod sealer. The utility model is characterized in that the upper part of the upper flange plate is connected with a lifting joint, the lower end of the wellhead device is an outer cone, the wellhead device is matched with the inner cone on the upper part of the lower flange plate, the upper part of the lower flange plate is an inner cone, and the wellhead device is positioned and matched with the outer cone on the lower part of the upper flange plate, The lower part is a boss, and the wellhead device is connected with the casing tee; the upper flange is connected with the end face of the lower flange.

　　What are the advantages of wellhead? How is it connected?
　　1. The wellhead device suspends part or all of the weight of each layer of casing except surface casing through hanger;
　　2. Connect wellhead equipment, such as BOP.
　　3. Wellhead equipment forms pressure seal between inner and outer casing strings;
　　4. The wellhead provides an outlet for releasing the pressure that may accumulate between 20% casing strings.
　　5. In case of emergency, wellhead equipment can pump killing fluid or fire extinguishing agent into the well from the side hole of casing head.