The invention discloses a recombinational streptomyces lydicus and application thereof. A construction method of the recombinational streptomyces lydicus comprises the step of guiding positive regulation genes synthesized by natamycin into streptomyces lydicus which is used as host bacteria to screen the positive regulation genes so as to obtain the recombinational streptomyces lydicus of which the natamycin yield is higher than the host bacteria; natamycin synthesizes proteins with the positive regulation gene codings as shown in a) and b): a) protein with the amino acid sequence as shown in SEQ ID No.1; b) protein which substitutes, deletes and/or adds one or more amino acid residues in the SEQ ID No.1, is related to natamycin synthesis and is derived from a). Compared with the wild type, the recombinational streptomyces lydicus obviously improves the natamycin yield and bacteriostatic ability, and can be applied to the aspects of food, biological energy source, feed addition and the like.