Abstract: In a proxy re-encryption scheme, an untrusted proxy can convert the cipher text encrypted by Alice to the cipher text encrypted by Bob. Certificateless proxy re-encryption scheme has the advantages that avoiding the complicated public key infrastructure (PKI) and solving the problem of key-escrow in identity-based cryptography. To deal with the disastrous result of key leakage, a certificateless proxy re-encryption scheme featured with key insulated function has been proposed in this paper. Security proof in the random oracle model and experiment results demonstrate that the proposed scheme is secure and practical. At last, a secure data sharing scheme for cloud-based mobile Internet has also been given based on the proposed encryption scheme.