To assess the risk that indigenous mosquitoes in China are capable of transmitting and sustaining West Nile virus (WNV), four important Culex mosquito species, Culex tritaeniorhynchus, Culex modestus, Culex pipiens pallens, and Culex pipiens quinquefasciatus, were allowed to feed on the artificial infectious blood meal with WNV dose of 106,8 plaque-forming unit/ml and tested ≈2 wk later to determine infection and transmission rates. The results indicated that four Culex mosquitoes were competent laboratory vectors of WNV. The infection rates and transmission rates were statistical differences among different species of mosquito (χ² = 20.620, P = 0.000; χ² = 15.020, P = 0.005, respectively). The highest infection rate and transmission rate were obtained with Cx. tritaeniorhynchus (87.5 and 74.2%, respectively).