An optical security method for protecting user password belongs to the field of information security. The method is characterized in that a newly set password is coded as follows: a new password P set by a user and a key K randomly generated are transformed to obtain a parameter for controlling OFS, then the parameter controls the OFS to generate a fractal pattern F, and the F and the K are stored in a storage media; the verified password is verified as follows: firstly, the verified password P' and the key K are transformed to generate a parameter for controlling the OFS, then the parameter controls the OFS to generate a fractal pattern F', the F' and the fractal pattern F stored in the storage media are compared, if the F' is in accordance with the F, then the user password passes the verification, or the user password is an illegal password. The method has the advantages that the application range of the optical security method is expanded to the user password protection, and the optical security method is safer than the existing cryptology method realized by computers or DSP and can be applicable to a plurality of situations using password verification.