The invention provides a power telecommunication network multi-domain fault diagnosis method under network virtualization environment. The method comprises three parts: SP fault deduction, SP belief evaluation, and multi-SN fault deduction; as SP fault deduction module computes a belief function value BF of each link fault probability, creates a fault propagation model according to each link faultprobability and the SO, and obtains a minimum fault set explanation syndrome set for explaining the observed syndrome, thereby effectively solving the problem that the underlying network informationis inaccessible; the multi-SN fault deduction module analyzes the syndrome, generates FPM abstracts, combines FPM abstracts of all SNs and performs the fault deduction, thereby effectively solving theproblems of the inter-domain propagation of multiple underlying network domains and the absence of the global information. The algorithm provided by the invention acquires the good accuracy rate andshort diagnosis time.