The number"e",which is the base of natural logarithm,is one of the basic mathematical constants.In nature,many laws are taken as exponential functions based on number"e"(the e-exponential law).The e-exponential law is widely found in fundamental theories of physical chemistry,such as thermodynamics,kinetics and statistical mechanics.The common e-exponential law in physical chemistry was summarized.The analysis showed that e-exponential law often originated from solving differential equation or taking the logarithm of the continuous multiplication to simplify the calculation.Understanding the law of the e-exponential law not only strengthened our grasp of physical chemistry theory,but also provided guidance for learning this scientific method.