In vitro experiments confirmed PKNOX2 effects in pathological myocardial fibrosis, through generating PKNOX2 overexpression and fibroblast-specific knockout mouse line, we found that PKNOX2 knockout aggravated cardiac disfunction and exacerbated cardiac fibrosis, while PKNOX2 overexpression had an opposite effect in TAC induced heart failure mice. This evidence concerns the gene PKNOX2 and Myocardial fibrosis.