In order to investigate the effect of CAPN1 on broiler tenderness traits, its CDS was analyzed with PCR-SSCP and DNA sequencing, and the genotype analyses covered individuals from five purelines and three crossbreds. Primers for exon5 and exon6 of CAPN1 were designed from database of chicken genomic sequence. The frequency of allele and PIC were calculated. A C/T mutation at base position 2546(site A) and a G/A mutation at base position 3535(site B) were found among individuals in each line. The least square analysis showed that three genotypes of birds had significant correlation with fiber density and partial carcass traits in site A and B. It was concluded from the results that CAPN1 gene may be the major gene affecting the tenderness traits of chicken or it links with the major gene, and the the polymorphic site may be used as molecular markers for meat tenderness and chicken quality.