Disclosed are a blowing method for an efficient vanadium extraction-decarburization dual converter with a long service life and a system thereof. The method comprises: introducing a vanadium extraction converter coal gas and a decarburization converter coal gas into an oxygen burner; obtaining a CO2-N2 mixed gas with a first purity via the vanadium extraction converter coal gas; obtaining a CO2-N2 mixed gas with a second purity via the decarburization converter coal gas; obtaining an O2-CO2-N2 mixed gas via the decarburization converter coal gas; obtaining a CO2 gas with a first purity via the CO2-N2 mixed gas with a second purity; using the CO2-N2 mixed gas with a first purity for vanadium extraction converter bottom blowing; using the CO2-N2 mixed gas with a second purity as an iron ore powder carrier gas of vanadium extraction converter blowing; and using the O2-CO2-N2 mixed gas and the CO2 gas with a first purity as a lime powder carrier gas of decarburization converter bottom blowing and decarburization converter bottom spraying. The method and system increase the vanadium oxidation rate of a vanadium extraction converter, improve the dephosphorization effect of a decarburization converter, and prolong the service life of the vanadium extraction converter and the decarburization converter.