Abstract: Based on the status quo of digital publishing in the publishing industry，firstly，this article directly faces the actual needs of digital transformation of traditional small and mediumsized publishing houses， and uses case analysis to study the connotations and models of thirdparty digital publishing platforms. It is considered that the main building bodies of current thirdparty digital platform are Internet，IT technology companies and large traditional publishing groups. Secondly， based on the differences in participation links and service content， the service models of third-party digital publishing platforms are summarized into four categories for content production， content marketing， management collaboration， and the entire process of digital publishing. Finally， on the basis of the above theoretical research and case analysis， it discusses the existing problems and optimization strategies of third-party digital publishing platforms. It is believed that the government， industry associations， publishing houses， platform parties and other entities should open up cooperation， reconstruct business thinking and in the industry value chain， make good use of thirdparty digital publishing platforms to contribute to deepening the reform of the publishing industry.

Key words: Third-party digital publishing platform Connotation Model Optimization