The invention provides a conformance testing adapter based on TTCN-3. The conformance testing adapter comprises a testing project and control interface, a terminal interactive message codec, a terminal interactive message transceiver, a system configuration message processor, an external function call processor, a platform adapter body, a complete encryption algorithm processor and an API adapter body, wherein the terminal interactive message codec is connected with the testing project and control interface, the terminal interactive message transceiver is connected with the terminal interactive message codec, the system configuration message processor and the external function call processor are connected with the testing project and control interface, the platform adapter body is connected with the external function call processor, the complete encryption algorithm processor is connected with the platform adapter body and the API adapter body is connected with the terminal interactive message transceiver and the system configuration message processor. By adoption of the adapter, adaptation of a TRI and an open API of a testing instrument is achieved, and architecture of a TTCN-3 testing system defined in the standard issued by the ETSI is achieved.