This article focuses on the continuous development of equal cooperation between nonprofit organizations in Chinese society over recent years. It attempts to explicate this phenomenon as a manifestation of accelerated structural differentiation of Chinese society as organic solidarity is formed. This article adopts Durkheim’s concept of “organic solidarity” to frame the features involved in this phenomenon, such as autonomy in defining objectives of voluntary cooperation, and equal consultation as an indicator of the level of development of China’s civil society. This is done in order to understand the mechanism by which horizontal linkages are created in contemporary Chinese society, and what their positive significance is for the healthy development of Chinese civil society. In view of this, the author further believes that at the same time we consider social science, we can only achieve a better understanding of China’s current development into a modern, complex society by considering social differentiation and solidarity as well.