Abstract: Two-phase short-circuit on one side of transformer is one of the most dangerous transformer faults, which will affect the stability and reliability of the whole power system. In order to determine the relationship between the three-phase current on the other side of the transformer furtherly when the two-phase short-circuit occurs on one side of the transformer, the symmetric component method is used to derive and analyze the relationship between the three-phase current on the high-voltage side when any two-phase short-circuit occurs on the low-voltage side of the transformer connected with Ynd11 and Yyn0 respectively. The above results summarize the fault waveform of two-phase short-circuit fault on one side of transformer, which can provide reference for the fault analysis of power practitioners.