The invention relates to the field of oil cylinder machining equipment, in particular to an oil cylinder clamping mechanism convenient for adjusting a welding angle. The oil cylinder clamping mechanism comprises a clamping box which is a hollow box body, wherein swinging motors are arranged on two sides of a hollow part; each swinging motor is connected with a swinging block; the swinging blocks are fixedly connected with a swinging plate which is located at the hollow part of the clamping box; the middle part of the swinging plate is provided with a material bearing base matched with the bottom of an oil cylinder shell; and clamping devices matched with the oil cylinder are arranged on outer sides of the material bearing base. The invention aims to provide the oil cylinder clamping mechanism for adjusting the welding angle; the swinging plate is driven to swing at a certain amplitude by the swinging motors; the material bearing base and the clamping devices matched with the oil cylinder are arranged on the swinging plate; and then the welding angle of the oil cylinder can be adjusted, so that more high-efficient welding at certain parts can be realized, and then whole welding efficiency is improved.