The invention, which belongs to the field of power system transformation engineering, relates to a 10-kV bus differential protection method based on a process layer networking mode of a smart substation. Since the traditional substation 10-kV bus is not configured with bus differential protection, faults can not be cut and removed rapidly; and the 10-kV bus fault is removed by relying on the long-term backup protection like over-current protection of the low-voltage side of the main transformer, so that the safety of the primary equipment and the stability of the distribution network are affected. According to the invention, on the basis of the information sharing of intelligent substations, interlocking and starting conditions are added for the bus differential protection logic, the application of 10-kV bus differential protection is realized; the bus fault can be removed rapidly; the primary equipment is protected; and the operational reliability of the substation is improved.