Since the initial report of mosquito resistance to insecticides in the 1940s, such resistance has rapidly spread worldwide, presenting a significant challenge to the control of various diseases transmitted by mosquitoes as vectors. The voltage-gated sodium ion channel (VGSC) serves as the target for pyrethroid insecticides. Mutations occurring in the active site of VGSC can disrupt the binding of insecticides to VGSC, resulting in knockdown resistance (kdr) and compromising the effectiveness of insecticides. Understanding the kdr mutation is fundamental to comprehending the molecular mechanisms underlying insecticide resistance and to the development of molecular detection technologies for such resistance. This review provides a concise overview of the insecticide resistance mechanisms in mosquitoes, the structure of VGSC, and delves into the kdr mutations found in five key vector mosquitoes in China (Anopheles sinensis, Aedes albopictus, Aedes aegypti, Culex quinquefasciatus, and Culex tritaenioides), exploring their correlation with pyrethroid insecticide resistance. The insights from this review hold significant value for studying VGSC kdr mutations, understanding the three-dimensional structure of VGSC, elucidating the molecular mechanisms underlying resistance to kdr mutations, and furnishing a theoretical framework for the future development of molecular detection techniques for insecticide resistance.