When the index (price) shows an upward trend, the turnover exceeding 1 10,000 is the backbone to promote the index (price) to rise, which is defined as the main capital inflow, and vice versa. The difference between the two on the same day is the net force to push the index up after the two forces offset on the same day, that is, the net inflow of the main funds of the plate or individual stock on the same day. In other words, the main capital flow predicts the strength of the power to promote the rise and fall of the index, reflecting the degree of people's bearish or bullish on the sector or individual stocks.