A graphene-coated microfiber (GCM)-based hybrid waveguide structure formed by wrapping monolayer graphene around a microfiber with length of several millimeters is pumped by a nanosecond laser at ～1550 nm, and multiorder cascaded four-wave-mixing (FWM) is effectively generated. By optimizing both the detuning and the pump power, such a GCM device with high nonlinearity and compact size would have potential for a wide range ofFWM applications, such as phase-sensitive amplification, multi-wavelength filter, all-optical regeneration and frequency conversion, and so on.