Aiming at the widely used digital production line and facing the digital twinning technology, this paper proposes a real-time monitoring and diagnosis method of the transmission chain status of the production line based on the digital twinning. First of all, the failure and failure mechanism of the conveyor chain is studied, and then a real-time data monitoring method is proposed according to the failure mechanism. On this basis, a data processing and analysis model oriented to the digital twin model is constructed. Then, artificial intelligence algorithm is incorporated into the model to improve the ability of the twin model to independently judge the failure and failure of the conveyor chain. Finally, the feasibility and efficiency of the proposed method are verified by experiments. The accuracy rate of fault diagnosis reaches 98.02%.