The present disclosure relates to an M2-LVP-K1 virus including a colorectal cancer cell-specific mutant sialic acid binding domain and a composition for treating colorectal cancer including the same. The mutant sialic acid binding domain of the present disclosure is constructed using directed evolution technology, and is a recombinant Newcastle disease virus constructed by substituting a normal sialic acid binding domain for a HN protein, a cell-binding receptor, to improve the specific infectivity to HCT116 cells. It was identified that M2-LVP-K1 recombinant Newcastle disease virus with improved colorectal cancer cell-specific infectivity has improved HCT116 cell death effect compared to the conventional normal recombinant Newcastle disease virus, and produces an excellent effect in inhibiting cancer tissue growth through in vivo experiments. The mutant recombinant Newcastle disease virus presented in this study relates to a therapeutic viral agent capable of inducing clinical symptom reduction, partial remission, or complete remission through colorectal cancer cell death or colorectal cancer tissue shrinkage.