China’s rice breeding has undergone several significant breakthroughs, including the development of dwarf rice, hybrid rice, and super rice. Among these, the utilization of heterosis has consistently remained the core and a challenging aspect of research. With the continuous innovation of breeding technologies, the development of hybrid rice has constantly advanced to new stages. In 1975, the Liaoning Academy of Agricultural Sciences employed the “indica-japonica bridging” technique to successfully introduce the restoring gene from indica rice into the japonica rice restorer line C57. This led to the development of the japonica hybrid rice combination Liyou 57, which was subsequently widely promoted in production, significantly enhancing the yield per unit area in northern rice-growing regions. Over the past 50 years, three generations of researchers at the Liaoning Academy of Agricultural Sciences have persistently dedicated themselves to the research and innovation of japonica hybrid rice breeding and related key technologies. They have accumulated a wealth of breeding materials and continuously improved the breeding theory and technical system. In the past decade, by integrating biotechnology and molecular breeding approaches, and relying on technologies such as combining ability analysis, construction of heterotic groups, and heterosis prediction, the genetic effects and compositional mechanisms of heterosis in northern japonica hybrid rice have been further clarified. This has promoted the deep integration and coordinated development of theoretical research on heterosis and breeding practices.