Abstract: 【Purpose/significance】In the era of big science,open access plays a vital role in scholarly communication,promoting the dis‐semination and innovation of knowledge. Furthermore,open access speeds up the socialization process of open science and academic achievements. We analyze the impact diffusion of open-access papers,which is conducive to the fine-grained evaluation of the impact of open-access papers.【Method/process】From the perspective of open access paper communication,this paper analyzes the impact dif‐fusion of open-access papers in the field of LIS between China and the USA through the knowledge network of open-access papers,output standards,and active degree Altmetrics【. Result/conclusion】It is found that there are differences in the knowledge network,out‐put standards,and active degree Altmetrics of open-access papers in the scholarly communication between China and the USA【. Inno‐vation/limitation】From the perspective of scholarly communication,this paper reveals the impact diffusion of open-access papers in the field of LIS between China and the USA through the usage and output standards of published open-access papers. Future studies need to conduct a fine-grained analysis of impact diffusion to comprehensively and deeply explore the knowledge units presented by impact diffusion.