Abstract: Technology and demand are two important sources of innovation. Since there is a trajectory describing technological progress, there must be a trajectory describing the evolution of demand. Comparing the research progress of scholars on the technical trajectory, it is clear that the research on the demand trajectory is still in its infancy, such as whether the morphological characteristics of the demand trajectory are similar to the S-curve of the technical trajectory, and whether the new and old demand changes process is similar to the replacement process of new and old technologies. The question was not answered clearly. Selecting the evolution of demand for Chinese TV products from 1978 to 2018 as the research object summarizes and discusses the market replacement process for color CRT TVs. It is found that the consumer value proposition drives the continuous improvement of technical performance, and the synergy between price and technical performance constitutes two aspects of the evolution of demand. Through the technical performance and price curve of the demand structure, the demand evolution trajectory defined by the demand trajectory. The research results show that, the demand trajectory is composed of technical performance trajectories and price trajectories. The shape of the demand trajectory is the result of the combination of technical performance trajectories and price trajectories. Among them, the technical performance trajectory is a continuous curve with a slope upward, and there is no discontinuous characteristic.The continuous consumer demand desires to pull the relay connection of multiple intermittent technical trajectories. The price trajectory is composed of a number of intermittent curves, each of which is a curve with a downward slope. In theory, the research results provide new insights into the complex relationship between demand and technological development. In practice, the research results provide reference for late-developing companies to understand the rules of new products entering the mainstream market, provide reference for enterprises to launch new product advertising and marketing strategies, and also recognize the importance of technology in promoting product innovation for late-stage enterprises. Point to lay the foundation.