To provide an orifice plate for an engine mount filled with MR fluid that efficiently controls flow characteristics of MR fluid.

An orifice plate apparatus for an engine mount filled with magnetorheological (MR) fluid includes: a coil assembly having a coil wound thereon and being annular in shape; and a core assembly unit housing the coil assembly, formed in a discoid shape, and defining a flow path of which one inlet/outlet may be disposed in a top surface of the core assembly unit, and the other inlet/outlet may be disposed in a bottom surface of the core assembly unit. The flow path may be formed annularly along a perimeter of the coil assembly. A flow path separator is installed between the upper inlet/outlet and the lower inlet/outlet, such that only a unidirectional circulation may be enabled for the MR fluid passing through the flow path.