The invention discloses a V/F mode and P/Q mode seamless switching control device of a PCS converter. The V/F mode and P/Q mode seamless switching control device of the PCS converter comprises a current collecting module, a first voltage collecting module, a second voltage collecting module, a reference signal computing module, a phase synchronizing module, a voltage reference signal generating module, a voltage loop regulation module, a current loop regulation module, a power scheduling module, a first switching switch, a second switching switch and a pulse width modulation module. The V/F mode and P/Q mode seamless switching control device of the PCS module achieves seamless switching of the PCS converter from a V/F working mode to a P/Q working mode, avoids any current or voltage overshoot once the switching happens and ensures stable operation of the PCS converter all the time.