The present invention relates to application program logs. In particular, the invention relates to a method and a system in which an original log method of an application program is optimized and newly injected to the application program. According to one aspect of the present invention, there is provided a method for optimizing an application program log record, comprising: identifying an original log method of an application program; separating a character string parameter in the original log method into a constant part and a variable part; establishing a correspondence flag between the constant part and the variable part; constituting an optimized log method by the constant part, the variable part and the correspondence flag; and replacing the original log method with the optimized log method through a code injection. With the above method, the hard disk storage amount of the log record and the IO operation frequency can be reduced.