The invention discloses a simulation device based on a JTAG protocol. The device comprises a parallel bus interface, a JTAG interface, a JTAG simulation processing IP core and an interface conversion unit. One end of the JTAG simulation processing IP core is connected with a debugging host through the parallel bus interface and the interface conversion unit, and the other end of the JTAG simulation processing IP core is connected with a target chip through the JTAG interface. The JTAG simulation processing IP core receives debugging data of the debugging host through the parallel bus interface and the interface conversion unit, converts the data into JTAG data and outputs the JTAG data to the target chip through the JTAG interface. The JTAG simulation processing IP core receives the JTAG data of the target chip through the JTAG interface, converts the JTAG data into data conforming to the parallel bus protocol, and outputs the data to the debugging host through the parallel bus interface and a communication interface conversion unit. The simulation device has the advantages that the structure is simple, the JTAG simulation function can be achieved on the basis of the IP core, the simulation speed is high, and universality and expansibility are high.