The invention discloses a transformer safety state assessment based on oil chromatography, comprising steps of determining an oxygen-containing type of a transformer according to the nitrogen-oxygen rate inside the transformer, obtaining preset fault energy intensity threshold L1,L2and L3 according to the oxygen-containing type of the transformer, obtaining the dissolving content X1, X2, X3 and X4 of the methane, the ethane, the ethene and the acetylene in the transformer, calculating fault energy intensity P according to the X1, X2, X3 and X4, calculating transformer fault energy intensity index PI according to the L1, L2, L3 and P, and determining the safety state of the transformer according to the PI. The transformer safety state assessment method based on oil chromatography disclosed by the invention has less set thresholds by comparing with the DGA method which is commonly adopted, has simple calculation logic and has higher reaction sensitivity to the safety condition caused by server faults like the high energy overheating and arc discharge.