Provided is a diaphragm mounting of a brake chamber for a vehicle, and in particular, to a diaphragm mounting of a brake chamber for a vehicle, which may exclude a return spring for restoring a diaphragm to an original position. The diaphragm mounting of a brake chamber for a vehicle includes a spring diaphragm assembled between a head and a flange case, a push rod having a top surface closely adhered to a bottom surface of the spring diaphragm, a piston located between the head and the spring diaphragm, and a power spring disposed between a top surface of the piston and a bottom surface of the head to pressurize the piston with an elastic force, wherein a center hole is formed at the center of the spring diaphragm, and the push rod located below the spring diaphragm and the piston located above the spring diaphragm are integrally connected by a coupling unit through the center hole.