The invention discloses a method for monitoring the performance of metro Ethernet. The method comprises traffic statistics of an Ethernet port and statistics based on the SLA flow. When the monitoring is carried out on the traffic statistics of the Ethernet port, connection between the ports of two interchangers is ensured firstly, and then the monitoring function is carried out globally and the flow statistics function of the Ethernet port is achieved under the connected ports. When monitoring is carried out on the statistics based on the SLA flow, normal communication between the two interchangers based on Y.1731 is ensured firstly, and then the monitoring function is carried out globally and the statistics function based on the SLA flow is achieved in the SLA mode. Finally, corresponding statistics results are displayed according to minimum statistics time intervals respectively. The method for monitoring the performance of the metro Ethernet achieves organic integration of the interchangers and an Ethernet performance testing meter, is capable of carrying out long-time online monitoring on performance indexes of the Ethernet such as port flow statistics property, time delay, delay variation and packet loss probability, has an Ethernet performance index ultralimit network management warning function, and has guiding significance for effective management and maintenance of the metro Ethernet.