The invention discloses a variable capacity type fluid pump. The fluid pump comprises shells, a swash plate, a cylinder column, a piston assembly, a check ring and an inclination adjusting part; a driving space is formed inside the shells; the swash plate is arranged in the driving space, can be installed in a rotating mode by taking supports as the center, and can adjust the inclination angle ofan inclination surface; the cylinder column is installed in the driving space and can rotate under the action of a driving shaft, and multiple air cylinder holes are formed in the inner part of the cylinder column along the direction parallel to the driving shaft; at least a part of the piston assembly is inserted into the interiors of the air cylinder holes of the cylinder column, and the pistonassembly is subjected to linear movement in the air cylinder holes while rotating along the cylinder column; the check ring is connected to the piston assembly, and rotates along with the piston assembly in the state that the piston assembly is attached to the inclination surface of the swash plate; and the inclination adjusting part enters and exits from the driving space through the shells, andin the process that the inclination adjusting part is inserted into the driving space, the inclination angle of the swash plate is adjusted by utilizing the tail end of one side of the inclination adjusting part to push the bottom surface of the swash plate.