The invention discloses a billing method, a billing device and a billing system and relates to the technical field of mobile communication. According to the invention, according to at least one amongservice use condition of a user in a preset period, the remaining sum of the user and the credit condition of the user, pre-judgment is made on the consumption condition of the user and billing is performed through sending a billing message of the user in the next preset period to an online billing system or sending a telephone bill of the user in the next preset period to an offline billing system. A billing strategy for the user can be adjusted dynamically instead of simply sending the telephone bill of the user to the online or offline billing system merely according to whether the user isa prepaid user or a post-paid user. Through setting pre-judgment conditions or condition combination, characteristics of the online billing system and the offline billing system can be utilized reasonably and effectively for user billing, so that arrearage of the user and resource waste can be reduced.