The invention discloses an integrated test system and a relevant method for distributed software systems. The system comprises a test server, at least one test client end and at least one test agent; the test server is respectively connected with the test client end and the test agent, in order to fulfill test on external systems under test according to test information; meanwhile, feed the test results back to the test client end; the test client end is used to receive and transmit test information, control the test server to perform tests, and receive test results; the test agent is also linked to a system under test through an interface for the system under test, in order to monitor message that are received and transmitted through the interface; meanwhile, the test agent is respectively interactive and adaptive with the test server and the system under test, and receives and transmits test message as well as relevant response message. Therefore, the invention adapts to test the second generation of distributed software systems that are fulfilled with distributed computation technology, increases and improves test tool expansibility and integrated test efficiency, and makes for execution of all types of integrated tests and guarantees quality of software products.