The invention discloses a security password manager based on multi-cloud storage and a use method thereof, the use method comprises the following steps: for accounts and password information of a useron any website, firstly, adopting a (k,n) threshold secret sharing algorithm (combining RAONT-RS algorithm with Shamir algorithm); encrypting information, splitting the encrypted information into n parts, improving the reliability of data by adopting a commitment scheme, and storing the data at n cloud providers; when the password is obtained, the commitment scheme verifying the data firstly, then combining the at least k parts to restore the ciphertext, and finally obtaining the plaintext account and password information through decryption. According to the password manager, the problem of data reliability existing in the multi-cloud storage password manager is solved, the robustness of the password manager under attack is improved on the basis that the data storage security is guaranteed, and meanwhile efficient retrieval can be achieved.