Fault-sensing and protecting apparatus for soft start circuit of inverter and method for the same are proposed. The soft start circuit of inverter includes a soft-starting resistor and a relay. The relay has a normally-open end connected to the soft-starting resistor in parallel. The fault-sensing and protecting apparatus for soft start circuit includes a central processing unit (CPU) and a photo coupler. The CPU is electrically connected to the inverter and an input end of the relay, respectively. The photo coupler includes a light emitting diode (LED) and a photo transistor. The LED is first electrically connected to a resistor in series and then electrically connected to the soft-starting resistor in parallel. The photo transistor is electrically connected to CPU. After the inverter starts to work, the CPU cuts out voltage applied to the inverter if the LED is lit. Therefore, the inverter can be prevented from damage.