The trustworthiness of safety-critical systems(SCS) is very important.Assessing the trustworthiness mainly depends on data from test.In order to ensure the reliability and validity of test data, especially for such complex systems, manual testing is infeasible in practice.Development of test languages as effective way to implement automatic testing is inevitable trend for automatic testing of SCS.As in general test language for SCS, testing should be independent of specific equipment, including SCS(SCS under test) and test equipment.In the paper, the issues of equipment collaboration are discussed.Aiming at high order and real time characteristics of equipment collaboration during testing, types and expressions of equipment collaboration involved in test of SCS are proposed, and the syntax of statements of equipment collaboration is defined.Then by defining the evaluating rules of these equipment collaboration expressions, semantic rules of statements of equipment collaboration are specified, and related properties are proved to show the soundness of these semantic rules.This work demonstrates that the equipment collaboration is dynamic and open, and the test languages of SCS can be general.