Abstract Background A splice mutation that causes skipping of exon 17 in the KIT gene is a major reason for the dominant white phenotype of pigs. Exon 17 of the KIT gene may be related to differences in testis size and sperm quality among different pig breeds. Investigating the effects of exon 17 of the KIT gene on spermatogonia differentiation and testicular development is essential for understanding the genetic causes of reduced fertility and semen quality in pigs. To better understand the effects of the splice mutation of KIT on porcine spermatogenesis, we described an exon 17 deletion mouse model (Kit D17/+) constructed by simulating splice mutations in KIT for functional verification. Results Deletion of exon 17 of Kit severely impaired the differentiation of spermatogonia and promoted the apoptosis of germ cells, resulting in testicular dysplasia and decreased sperm quality and male fertility. Further transcriptomic analysis revealed inhibited expression of genes involved in meiosis and spermatogenesis and attenuated MAPK-ERK signaling in the testicular tissues of Kit D17/+ mice. The attenuated MAPK-ERK signaling caused by impaired Kit phosphorylation was confirmed by western blotting. Conclusions Our study demonstrated that deletion of exon 17 of Kit severely impaired spermatogenesis and testicular development, leading to decreased semen quality and male fertility. These findings verified the function of exon 17 in the Kit gene and provide a theoretical basis for improving the semen quality of dominant white pigs through correction of the splice mutation of KIT.