Abstract: Based on the analytical framework of the expansion of technological prospects, two-dimensional structural transformation of economic complexity, and breakthrough of the "stagnation trap" of middle-income countries, this paper constructs a set of network indicators reflecting the evolution characteristics of product space structure. Using the export products data of 133 countries from 1962 to 2019 obtaining: (1) Measuring the " Prospect coefficient for technological upgrading of Potential Advantageous Products" yields information on the national capability accumulation, which is correlated with the country's economic complexity to obtain a visualization of the non-linear evolution of technological prospects. The "S" curve formed shows that middle-income countries are facing a jump in capability from irrelevance to relevance between the expansion of technological prospects and economic complexity, and only very few countries can cross the sparse zone in the middle part of the curve, climbing from the bottom to the top of the curve, and ranking among developed countries. China, like Japan and South Korea, is one of the few countries that have caught up and moved out of the sparse zone in the middle of the curve. (2) On the basis of measuring the two-dimensional structural indicators of product diversity and heterogeneity in the economic complexity of 133 countries, a comparison between China, Japan, and South Korea reveals that China is currently undergoing a two-dimensional structural transformation of economic complexity, similar to what happened in Japan and South Korea when they broke through the "stagnation trap" and entered the high-income countries, and the product heterogeneity index has been greatly improved during the deep structural adjustment, but the two-dimensional transformation from product diversity to heterogeneity has not been completed yet. (3) By visualizing the four-phase evolutionary characteristics of China, Japan and South Korea's product space and targeting the progressive capacity of government policies behind it, we can provide a decision-making basis for China to successfully complete the two-dimensional structural transformation, expand its technological prospects and break through the "stagnation trap" to realize high-quality development under the conditions of the new round of technological revolution and industrial change by drawing on the experience of Japan and South Korea in grasping the "second window of opportunity" for the digital economy and green development technology.