The results of the landscape-radioecological monitoring and geoinformation modeling of the distribution of 137Cs in the Predpolesie landscapes (Vyshkov and Dubrovka sites), as well as in the Opolies (wide woodless plains) landscapes (Brakhlov and Kostitsa sites) in the Bryansk oblast are presented. The data on the radiation survey of arable lands in the Bryansk oblast carried out in 2017 at four test sites with different densities of 137Cs contamination are given. Based on the monitoring results, a data bank of the vertical distribution of 137Cs in the agrocenoses soils has been formed. The structure of the large-scale radioecological geoinformation system (RadGIS) comprises a digital terrain model based on the radar survey of the Earth topography from the SRTM shuttle. The second information layer contains the results of the aerial gamma (AG) survey performed in 1993 with a resolution of 100 m. A comparative analysis of the 2017 ground testing data with the results of the 1993 AG survey has allowed for assessment of the 137Cs radioactive contamination field transformation in various landscapes at four test sites. To assess the intensity of 137Cs lateral migration at the test sites, geoinformation modeling has been performed with the detection of surface flow streamlines.