Securities are all kinds of economic rights and interests certificates, and also refer to specialized products. It is a legal document used to prove that the holder enjoys certain rights. Mainly including capital security, currency securities and commodity securities. In a narrow sense, securities mainly refer to securities products in the securities market, including property market products such as stocks, debt market products such as bonds, and derivative market products such as stock futures, options and interest rate futures. The subject system of securities science is an organic system composed of various branches that study the behavior characteristics and operating rules of the securities market from different angles, mainly including two research fields: traditional securities theory and evolutionary securities theory.

Stock trading is to engage in stock trading. The core content of stock trading is to obtain profits through the price difference between buying and selling stocks in the securities market. The rise and fall of stock prices change with the fluctuation of the market. The fluctuation of stock price often shows the characteristics of differentiation, which stems from the concern of funds, and the relationship between them is like the relationship between water and ships. When the water overflows, the ship is high (the stock price rises when the capital flows in), and when the water runs out, the ship is shallow (the stock price falls when the capital flows out).