The invention discloses a micro inverter of a solar power generation system, and an operation method thereof. The method comprises the following steps: first of all, obtaining an output power value of a solar photovoltaic module, then, determining whether the micro inverter starts a power boosting mode, if the micro inverter starts the power boosting mode, boosting the maximum output power value of the micro inverter from a rated output power value to a maximum output power value, finally, determining whether the output power value of the solar photovoltaic module is greater than the maximum output power value, and if the output power value of the solar photovoltaic module is greater than the maximum output power value, the output power of the micro inverter being the maximum output power value. According to the invention, by use of the characteristic that the temperature of a solar battery itself and the maximum output power are negative temperatures, the solar photovoltaic module is enabled to output higher power when being operated in a low-temperature environment, the operation alternative of the power boosting mode is provided, the generating efficiency is improved, the generating cost is reduced, and the system application adaptability is enhanced.