The invention discloses a method of testing stability of an Ethernet exchanger, including: 1, connecting all the ports of a sample machine to a flux generator; 2, setting port mode as self-adapting, closing flow control function, to make all the ports in a default state; 3, setting port speed of the generator as line speed and frame length random; also including: at least one of full-load testing, flux impact testing, sustained operation testing, limit testing and environmental stress testing, combined in arbitrary sequence to completely test stability of the Ethernet exchanger. Compared with existing techniques, it has broad covering area, high efficiency, remarkable effect and high resources utilization, achieves testing purpose, saves testing time and expenses, and enhance success rate of testing, and avoids heavy losses of users and product suppliers.