The invention provides an excitation source and a function verification method. An excitation generating module in the excitation source is used for generating first packet flow used for testing a to-be-tested module, and respectively sending the first packet flow to an interface module and a packet verification module. The interface module is used for sending the first packet flow to the to-be-tested module to enable the to-be-tested module to process the first packet flow to obtain second packet flow, and sending the second packet flow to a response receiving module. The response receiving module is used for receiving the second packet flow, and sending the second packet flow to the packet verification module. The packet verification module is used for verifying, according to the first packet flow and the second packet flow, whether a function realized by the to-be-tested module is correct, and obtaining a verification result. Technical effects that supplement verification can be carried out on the packet flow through the packet verification module, and it is guaranteed that the verification result in verifying function correctness of the to-be-tested module has comprehensivenessare achieved.