Abstract: The emissions of 50 in-use gasoline light-duty vehicles were tested under simple loaded mode conditions, including transient loadedmode (IM195), short transient loaded mode (IG195) and steady-state loaded mode(ASM), and the new vehicle emission certification mode (NEDC) condition according to the national emission standards. The results show that IM195 has the best correlation to NEDC. The correlation factor R² of CO, HC and NO can reach 0.7010, 0.7271 and 0.6609 respectively. The second is IG195, which R2 of CO, HC and NO are 0.5138, 0.4846 and 0.6245. And ASM including two mode conditions has the worst correlation. The R² of CO, HC and NO under 5025 mode condition are 0.4109, 0.4481 and 0.5449. Under 2540 mode condition, the R² of CO, HC and NO are 0.3644, 0.3395 and 0.4578. Meanwhile, different pollutants under the same simple loaded mode condition have different correlative coefficients comparedwith the results under the NEDC mode. The main reasons include different warm-up conditions, test modes, measuring principles of the analytical instruments andcontrol precision of the chassis dynamometer.