The invention relates to the technical field of photovoltaic power generation control, in particular to an autonomous mode switching control method for a photovoltaic converter in a microgrid system.The method comprises the following steps: 1, monitoring a DC bus voltage of the photovoltaic converter; 2, when the bus voltage value is within the rated value, enabling the photovoltaic converter toexecute an MPPT algorithm; 3, when the bus voltage value exceeds a first voltage threshold value, enabling the photovoltaic converter to execute a reverse disturbance observation method to limit the power; 4, when the bus voltage value exceeds a second voltage threshold value, enabling the photovoltaic converter to control power by changing the disturbance step length; wherein the step 2 comprisesthe substeps: if the photovoltaic power increment is positive and the voltage increment is positive, continuing to disturb the voltage in the positive direction; if the voltage increment is negative,disturbing the voltage in the negative direction; if the power increment is negative and the voltage increment is positive, continuing to disturb the voltage reversely; if the voltage increment is negative, positively disturbing the voltage.