The edge computing node plays an important role in the evolution of the artificial intelligence‐empowered Internet of things (AIoTs) that converge sensing, communication, and computing to enhance wireless ubiquitous connectivity, data acquisition, and analysis capabilities. With full connectivity, the issue of data security in the new cloud‐edge‐terminal network hierarchy of AIoTs comes to the fore, for which blockchain technology is considered as a potential solution. Nevertheless, existing schemes cannot be applied to the resource‐constrained and heterogeneous IoTs. In this paper, we consider the blockchain design for the AIoTs and propose a novel classified ledger framework based on lightweight blockchain (CLF‐LB) that separates and stores data rights at the source and enables a thorough data flow protection in the open and heterogeneous network environment of AIoT. In particular, CLF‐LB divides the network into five functional layers for optimal adaptation to AIoTs applications, wherein an intelligent collaboration mechanism is also proposed to enhance the across‐layer operation. Unlike traditional full‐function blockchain models, our framework includes novel technical modules, such as block regenesis, iterative reinforcement of proof‐of‐work, and efficient chain uploading via the system‐on‐chip system, which are carefully designed to fit the cloud‐edge‐terminal hierarchy in AIoTs networks. Comprehensive experimental results are provided to validate the advantages of the proposed CLF‐LB, showing its potentials to address the secrecy issues of data storage and sharing in AIoTs networks.