The invention discloses a 110kV substation main transformer dual-delay protection system. A resistor R111 and a resistor R101 are connected in series, and the resistor R101 is connected with a 35KV three-phase power transformer. A resistor R112 is connected in series with a resistor R102. A series connection part between the resistor R111 and the resistor R101 is connected with a connection part between the resistor R112 and the resistor R102 through a resistor R100. One end of a resistor R301 is connected with the 35KV three-phase power transformer, and the other end of the 35KV three-phase power transformer is connected with a resistor R302 and a resistor R311 through a switch K1. The other end of the resistor R302 is connected with a 110KV three-phase power transformer. The 110KV three-phase power transformer is connected with a resistor R003 through a resistor R002. One end of a resistor R001 is connected with the 35KV three-phase power transformer. According to the system provided by the invention, the power failure range is small, a fault point can be easily determined, and the operational reliability of a power grid is high.