A mutant capable of producing 1,4-butanediol and a method of preparing 1,4-butanediol using the same are provided. The mutant microorganism is prepared by introducing and amplifying genes encoding enzymes converting succinate into 4-hydroxybutyrate and 4-hydroxybutyrate into 1,4-butanediol in a microorganism capable of producing succinate. The method includes culturing the mutant in a medium containing carbohydrate and obtaining 1,4-butanediol from the culture. Thus, 1,4-butanediol, which is essential in chemical industry, can be prepared in a biological process.