This invention provides a method, tool, and application for improving the
gene editing efficiency of *
Eimeria tenella*. The *
Eimeria tenella* strain with KU80 deletion is obtained by knocking out the KU80
gene in *
Eimeria tenella* using a
CRISPR-Cas9
gene editing
system. Compared with existing technologies, the tool and method of this invention can significantly improve gene-targeted integration efficiency, significantly reduce random integration events of
exogenous DNA, and improve the accuracy and stability of gene editing. It is a universal gene editing platform that can be widely applied to
gene knockout, gene knock-in, and endogenous marker research. The strain using this tool can significantly shorten the screening cycle for positive recombinant strains, improve experimental reproducibility, and provide important
technical support for
functional genomics research on *Eimeria tenella*.