The characteristics of pollutants and boundary layer structure during two haze events in summer and autumn 2014 in Shenyang, Northeast China were comparatively analyzed, by using measurements of mass concentrations of PM10, PM2.5, O3, NO2, SO2, and CO, vertical profiles of meteorological parameters from a 100-m high tower, and radiosonde data. The results showed that PM concentrations increased rapidly during the two haze events, resulting in visibility decreasing to be 1400 and 405 m, respectively. The weak haze event on 16 June was characterized by high O3 but low NO2 mainly due to the photochemical reaction, while all the pollutants increased on 31 October during the severe haze event, which was affected by pollutants emission and meteorological conditions. PM2.5 concentration had a good correlation with friction velocity (u*) but did not have obvious relationship with , which means the haze events were largely affected by the dynamic effect of turbulence but less by the thermal effect of turbulence. According to the radiosonde data, a single inversion layer with inversion intensity of 1.6°C/100 m existed during the weak haze event, whereas double or even multiple stronger inversions occurred during the severe haze event, with the inversion intensity larger than 2–4°C/100 m. Such stable atmospheric conditions favored the accumulation of pollutants. Backward trajectory analyses showed that the weak haze event was probably contributed by pollutant transport from North China, whereas the severe haze event was generated mostly by local pollutants.