The invention discloses an industry real-time control Ethernet redundancy fault tolerance network system and a method, including at least two control domains and at least one public domain connected with all control domains, wherein, each control domain adopts multipoint crossed redundancy ring network structure, core nodal point equipments on cross points are all connected with primary nodal point equipment and backup nodal point equipment of the public domain. On the basis of the prior ring network redundancy, the invention also realizes the redundancy of the core equipments needing external communication; when a primary core exchanger fails, a core exchanger which works in the backup mode is switched to work in the primary mode, the switch time is quite short. The invention also increases the double redundancy function of a public domain exchanger, the RSTP protocol is applied to the connection between the public domain and the control domains, which considers requirements on quickness as well as simpleness. In the invention, the core exchanger of the control domains adopts the ACL or the cross VLAN to replace a special bridge, thereby reducing equipment category and possible fault points and lowering delay.