Software licenses are valuable resources in the Grid environment, and how to manage them efficiently has become an active topic of research for computational Grid. This paper proposes an approach for organizing and managing software licenses in Grid environment, based on which a grid-specific license manager of software sharing system is designed and implemented. The license manager is independent of local specific LMS (License Management Service), and suitable for various and dynamic license resources management in Grid environment. The backfilling algorithm combined with reservation mechanism makes it gets license efficiently.