The present invention relates to a plasmid-based CTX phage replication system and Vibrio cholerae strain that can be infected by CTX phage and can be used for cholera toxin production. More particularly, the present invention provides a Vibrio cholera variant strain, which expresses a toxT protein in which tyrosine at position 139 is substituted by phenylalanine through the point mutation of a toxT gene using a plasmid-based CTX phage replication system, and is used as a receptor strain which can improve CTX phage infection efficiency and allows a plurality of CTX prophages to simultaneously infect the strain and to be inserted into the chromosome thereof, which the consequent provision of the effect of increasing the production yield of a cholera toxin.