The invention relates to an insulation coordination method and system for a symmetric bipolar flexible direct current engineering converter station. The method is characterized by comprising the stepof preparing a plurality of lightning arresters, comprising a lightning arrester for connecting a transformer valve side, a bridge arm electric reactor valve side lightning arrester, lightning arresters among bridge arm electric reactor terminals, a direct current pole bus lightning arrester, a direct current line lightning arrester, a grounding electrode line lightning arrester, a metallic returnlightning arrester, a first neutral bus lightning arrester, a second neutral bus lightning arrester, a third neutral bus lightning arrester and a neutral point lightning arrester for connecting a transformer grid side, on the main connecting line of an existing symmetric bipolar flexible direct current engineering converter station; and insulation coordination for the symmetric bipolar flexible direct current engineering converter station is realized by determining the characteristic parameter of each lightning arrester, so that the overvoltage level of the converter station is greatly limited, and the engineering design difficulty and engineering investment level are reduced.