The invention provides a simulation method of an integrated defense system for enhancing coal enterprise power system power supply reliability, which comprises the following steps: determining a power supply mode of a coal enterprise power system; calculating and analyzing a relay protection setting value; determining the safe and stable operation control strategy of the coal enterprise power system; switching a standby power; and adopting auxiliary measures. According to the method, an overall, comprehensive and integrated assessment is carried out on the effectiveness of measures for enhancing the coal enterprise power system power supply reliability by a trend analysis, a short circuit current calculation, a static security analysis and a transient stability analysis.