The Semantic Internet of Things is the extension of the Internet of Things and the Semantic Web, which aims to build an interoperable collaborative system to solve the heterogeneous problems in the Internet of Things. However, the Semantic Internet of Things has the characteristics of both the Internet of Things and the Semantic Web environment, and the semantic data presents many new data features. We analyze the characteristics of semantic data and propose the concept of uniform knowledge graph, which can be smoothly applied in the environment of the Semantic Internet of Things. In the meantime, a semantic collaboration method based on uniform knowledge graph is designed to take the uniform knowledge graph as the form of knowledge organization and representation, which provides a good data basis for semantic collaboration by constructing semantic links to complete semantic relation between different data sets. Then, the semantic collaboration in the Semantic Internet of Things can be achieved in our study. The experiments show that our method has the potential to analyze and understand the semantics of user requirements and provide more satisfactory results.