Ten lightduty gasoline vehicles meeting China Ⅵ phase b emission standards with different power types (plugin hybrid and conventional gasoline engine) were selected to carry out WLTC cycle emission tests under normal and low temperature conditions in the lightduty vehicle environmentsimulated emission laboratory at an altitude of 1 914 m in Kunming. The emission characteristics and influencing factors of NH3 and PN (PN10 and PN23) from lightduty gasoline vehicles were studied in plateau environment. The results showed that the NH3 emission of exhaust gas increased significantly after TWC, and the emission factor for different types of China Ⅵ phase b lightduty gasoline vehicles under plateau environment reached 21.80-485.10 mg/km, which was significantly higher than the 26 mg/km NH3 emission factor of lightduty gasoline vehicles as stated in the Technical Guideline for Preparing the Ammonia Emission Inventory. The NH3 emission of light-duty gasoline vehicles with plugin hybrid and conventional gasoline engines is mainly concentrated in the low speed and medium speed segments, and the NH3 emission was higher in low temperature environment. Compared with PN23 emission, PN10 emission of plugin hybrid electric vehicles and conventional power lightduty gasoline vehicles increased by 21.11%50.21% and 12.00%38.47% respectively. At low temperature, the peak emission rates of PN10 and PN23 were 6.12×10¹¹#/s and 5.28×10¹¹#/s, which were about 2 orders of magnitude higher than the corresponding PN emission rates at normal temperature.