A method for measuring switching time of an Ethernet ring network, characterized by comprising: synchronizing local time of each node in the Ethernet ring network; when a switching occurs in the Ethernet ring network, each node recording its own start time of the switching and end time of the switching; and comparing the start time of the switching and the end time of the switching of each node to obtain a maximum end time of the switching and a minimum start time of the switching among all nodes, and calculating a difference between the maximum end time of the switching and the minimum start time of the switching to serve as the switching time of the Ethernet ring network; wherein the step of synchronizing the local time of each node in the Ethernet ring network comprises: in the Ethernet ring network, a node having a blocked port sending a synchronization protocol frame, which carries a current local time, to other nodes except the node itself; after receiving the synchronization protocol frame, said other nodes setting their respective local time as the time in the synchronization protocol frame. wherein the method for the node having a blocked port to send the synchronization protocol frame to other nodes comprises: the node having a blocked port sending the synchronization protocol frame to said other nodes according to a first period at first, and then sending the synchronization protocol frame to said other nodes continuously according to a second period until the port is in an opened state; wherein the first period is shorter than the second period. synchronizing local time of each node in the Ethernet ring network; when a switching occurs in the Ethernet ring network, each node recording its own start time of the switching and end time of the switching; and comparing the start time of the switching and the end time of the switching of each node to obtain a maximum end time of the switching and a minimum start time of the switching among all nodes, and calculating a difference between the maximum end time of the switching and the minimum start time of the switching to serve as the switching time of the Ethernet ring network; wherein the step of synchronizing the local time of each node in the Ethernet ring network comprises: in the Ethernet ring network, a node having a blocked port sending a synchronization protocol frame, which carries a current local time, to other nodes except the node itself; after receiving the synchronization protocol frame, said other nodes setting their respective local time as the time in the synchronization protocol frame. in the Ethernet ring network, a node having a blocked port sending a synchronization protocol frame, which carries a current local time, to other nodes except the node itself; after receiving the synchronization protocol frame, said other nodes setting their respective local time as the time in the synchronization protocol frame. wherein the method for the node having a blocked port to send the synchronization protocol frame to other nodes comprises: the node having a blocked port sending the synchronization protocol frame to said other nodes according to a first period at first, and then sending the synchronization protocol frame to said other nodes continuously according to a second period until the port is in an opened state; the node having a blocked port sending the synchronization protocol frame to said other nodes according to a first period at first, and then sending the synchronization protocol frame to said other nodes continuously according to a second period until the port is in an opened state; wherein the first period is shorter than the second period.