Adjusting the structure of secondary education and maintaining a reasonable enrollment proportion between senior secondary schools and secondary vocational schools is crucial for establishing a modern vocational education system and fostering a healthy educational environment. An examination of the evolution of China’s policy on education streaming between senior high schools and secondary vocational schools after junior high school reveals that the principle of “roughly equal proportion in general education and vocational education” was established after the reform and opening up, undergoing tests such as the market-oriented reform of the economy and employment, as well as the expansion of university enrollment. However, in recent years, disputes have arisen in the implementation of this policy, including disagreements regarding the ratio of general education to vocational education, the timing of streaming, and its effects. In the future, to strengthen the foundation of secondary vocational education and refine the modern vocational education system, post-junior high school education streaming should adjust the proportion of general and vocational education based on local conditions, and appropriately delay the streaming time. Additionally, it should enhance the vocational education system and the “streaming-exchange” mechanism in high school education, expand further study opportunities for secondary vocational students through examinations, promote curriculum reforms in senior high schools to facilitate intra-school streaming, and establish a national qualifications framework that fully integrates general and vocational education at the senior high school stage.