Provided is a power steering sensor assembly which is capable of maintaining a stable coupling between a sensing device and a housing without using a separate auxiliary member, and is mounted in an electric power steering system. The power steering sensor assembly includes a sensing device including a plurality of coupling projections formed on an outer circumferential surface thereof; and a first housing having the sensing device housed therein and including a plurality of coupling grooves formed on an inner circumferential surface thereof, the coupling grooves each having an upper end which is opened. When the sensing device is housed in the first housing, the coupling projections of the sensing device are inserted into the coupling grooves of the first housing, respectively, such that the sensing device is coupled to the first housing without being moved in a radial direction and an axial direction.