Rice seedling substrates in China have been studied since 1970s. Developing rice substrate is the key point to improve the mechanized planting technology. Appropriate substrate can enhance the rice seedlings quality which was suitable for machine-transplanted and conducive to the development of full mechanization in rice cultivation. This paper introduced the history of the rice substrates, types and properties. The problems for rice substrate study were analyzed and the development trend was also pointed out in this paper, which was beneficial to the research and extension of rice seedling substrate and could provide a reference for promoting the rice planting mechanization.