Abstract This paper mainly introduces the T-x phase diagram of two components in the phase equilibrium system from three aspects. The first is the simple introduction of the phase diagram of two components in physical chemistry; The second is a combination of simple phase diagram of two components; the third is the recognition of practical complex phase diagrams of two components. It can help students to understand and master the T-x diagram of gas-liquid, liquid-liquid and liquid-solid in the phase equilibrium system of two component. A good foundation is obtained for the practical application.
