The invention provides a starting and shutdown control method for a proton exchange membrane fuel cell. According to the method, a whole fuel cell stack is divided into a plurality of cell modules; each cell module is connected with a modularized discharging circuit which is composed of a control switch, an auxiliary load and a crystal diode in mutual series connection; each modularized discharging circuit and a main load circuit are in series connection and are respectively connected with the cathode end and the anode end of the fuel cell; an air source is connected with the anode end of the fuel cell through an air blow-down valve; and air is used to purge residual hydrogen at the anode. During starting control, hydrogen is used to purge the anode, and the auxiliary load is used to control the voltage of the cell; and during shutdown control, introduction of air and introduction of hydrogen are successively stopped, a closed system of the auxiliary load is used for discharging, and introduction of air is cooperatively used for purging of the anode. The invention has the following advantages: consumption of time during shutdown of the fuel cell is reduced; the concentration of residual oxygen at the cathode is lowered down; reversal of poles of a single cell in the modules is prevented, and the phenomenon of reversal of poles of the fuel cell in the processes of shutdown discharging and air purging is prevented; and the system of the fuel cell is more simplified and is convenient to operate.