Abstract: In view of problems of narrow band width and inconvenient operation in traditional Ethernet tester by use of ping packet method, the paper proposed a design scheme of 16-channel Ethernet tester based on C8051 single-chip microcomputer and FPGA module. The tester supports 16-channel Ethernet test, and its FPGA module can provide 16-channel external SMII, whose sending unit is used to receive configuration data of C8051 single-chip microcomputer and send corresponding Ethernet packet according to the configuration data, and receiving unit is used to detect and statistic received Ethernet packet and send the statistical information to C8051 single-chip microcomputer. The test result validated feasibility of the tester.