An RISC processor device and a method of emulating a floating-point stack operation thereof The processor device comprises: a floating-point register file containing a plurality of floating-point registers; a decoding section for decoding operation instructions of the RISC processor; a floating-point operation section connected to the decoding section; a control register for controlling the status of the floating-point registers and controlling the decoding section and the floating-point operation section to emulate a floating-point register stack using the floating-point register file. The decoding section includes a pointer register for maintaining a stack operation pointer and storing the value of the stack operation pointer; the floating-point operation section includes a pointer operation module for operating the pointer register, emulating the stack operation of the stack pointer of the pointer register, modifying and monitoring the phase of the stack pointer during emulating a floating-point register stack operation.