The theoretical usage of MACD is not mentioned here, but it can be found online. By compiling the source code of MACD indicator, we can analyze that it is based on the moving average system, so the composition of moving average is composed of approximate transaction cost, that is, MACD is an indicator to measure trading behavior, and trading behavior is the reaction of traders to market environment judgment, that is, the indicator will lag behind market information. This is not to say that the index is inaccurate, but that the index is a quantitative result of the market environment. The judgment of market environment in trading behavior can't rely entirely on indicators, but it is irrational to leave indicators completely. An indicator is like a ruler. They are measuring tools and auxiliary tools, but we can't just talk about indicators. You should comprehensively analyze the information of the target commodity, make quantitative auxiliary analysis through indicators, and finally get the judgment result. Never stick to the simple golden fork and deviate from these elements to make simple business judgments. You should know the logic behind these signals.