Using US NASA's Fire Information for Resource Management System (FIRMS) VIIRS V1 (or Visible Infrared Imaging Radiometer Version 1) active fire location vector data, ASTER GDEM (30 m, or Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model), Moderate Resolution Imaging Spectroradiometer (MODIS, 1 km) Normalized Difference Vegetation Index (NDVI) and Land Surface Water Index (LSWI), and Global Land Cover products (30 m), based on GIS, the dynamic changes in active fire events were quantitatively analyzed from provincial to national scales in Laos in 2012-2017. In addition, characteristics analyses of major physical geographic elements of VIIRS V1 active fires, including topography (elevation and slope), MODIS vegetation-moisture indices (NDVI and LSWI) and land cover types, were conducted in detail in the 2015 El Ni?o. The results showed that: (1) the number of active fire events in Laos increased first and then decreased in 2012-2017, with the peak in 2015. Active fires in Laos were mainly concentrated in the northern and central regions. Luang Prabang, Sayaburi and Savannakhet had the top number of active fires at the provincial level, while Vientiane City, Sekong and Xaisomboun in sequence ranked the last. (2) The relationship between the frequency of active fires in Laos and topographic factors (elevation and slope) in 2012-2017 was basically the same. Active fires primarily occurred in the hilly and low mountainous areas with elevations of less than 1000 m (86.10%) and slopes of less than 30° (92.45%). Among them, active fires in the northern region were concentrated in the mountainous areas with elevations of 500-1000 m and slopes of 10-30°, while others in the central and southern regions were concentrated in the hilly areas below 500 m and gentle slopes of 2°-20°. (3) Seasonally, the active fires in Laos mainly happened during the dry season (94.75%), with the most number in March and April (82.24%) and in the medium-high coverage vegetation area with NDVI of 0.4-0.8 (92.05%) and LSWI of 0.2-0.6 (75.70%). (4) Active fires were mostly distributed in the forests of Laos, especially in the northern part, while the counterparts in the central and southern parts mainly occurred in farmland, grassland and shrubland. (5) In summary, characteristics analyses of major physical geographic elements of VIIRS active fires can be used to determine its fire type, that is, active fires in Laos were mainly caused by swidden agriculture.