In order to deeply understand the thermal, dynamic mechanism and particle microphysical properties of a heavy pollution process in Beijing in spring, a study was conducted based on multiple data sources of environmental, meteorological, sounding, AERONET, ceilometer remote sensing and satellite remote sensing data. The results are as follows: 1) The synergistic observation of multi-source data shows that this pollution originated in the western part of China, with a wide range of impacts, and it constituted a severe pollution up to level 6 in Beijing, with the concentrations of PM2.5 and PM10 as high as 600 μg/m3 and 1000 μg/m3. 2) MODIS MCD19A2 MAIAC AOD data can well reveal the origin, intensity, transport and affected area of the pollution. MISR AOD shows that t microphysical properties of the pollution particle have the characteristics of large mode, non-spherical and non-absorption. 3) CALIPSO data shows that the depolarization was 0.1-0.5 and the color ratio was 0.5-1.3 at the altitude of 1-4 km, showing the phenomenon of ''small depolarization and large color ratio''. 4) AERONET data shows that before, during and after pollution, the AOD_550 nm values were 0.9, 2.0 and 0.2 respectively, and the AE_440-675 nm values were 1.30, 0.4 and 1.0 respectively, indicating that the pollution was a mixture of PM2.5 and PM10. 5) Radiosonde data show that the polluted atmospheric stratification of this pollution was very stable, and there were significant thermodynamic characteristics in each phase. Before the pollution broke out (May 3), the upper atmosphere was humid and the temperature decline rate was small, while the lower atmosphere was dry and rose, forming a convective space. During the pollution outbreak period (May 4), there was a multi-layer inversion and dry atmosphere sinking movement. Driven by the upper westerly wind and the lower southerly wind. At the end of pollution (May 5), the inversion in the lower layer disappears, the height of the inversion in the upper layer continues to rise, and the air was dry, and the wind speed in the deep westerly region continues to increase, ending the pollution process. 6) The results of Ceilometer monitoring and EC model results showed that the atmosphere was stable on May 4th, and the boundary layer was distributed evenly in space, with an atmospheric boundary layer height of about 1200 m at 08:00 and about 300 m at 20:00.