The article proposes a key management scheme for satellite networks targeting the problem of existing key management scheme cannot be suitable for satellite networks. Threshold secret mechanism is used to achieve the protection for system master key, and avoid the single point of failure problem. The certificateless cryptography is introduced to achieve secure distribution for public and private key pair, and the signcryption mechanism is adopted to achieve secure distribution for system master key share. The proposed scheme eliminates the requirement for a secure channel within the key distribution process, and avoids the key escrow problem. The scheme meets the security requirements, and has a high efficiency.