The present invention relates to a mutated virus. Said virus can be an influenza virus of human or other animal origin. The present invention also relates to a method for preparing the mutated virus, the method comprising introducing UAG codons into positions upstream of the stop codons per se of one or more genes of a viral genome by reverse genetic techniques. The present invention further relates to uses of the mutated virus, for example, as a live attenuated vaccine, or in replication of controllable and safe virus models, and the like.
