Abstract. In this paper, the chemical, rheological and elasticity properties of sulfur and natural rubber modified bitumen (RSMB) were investigated. Sulfur (GOST 127-93), natural rubber and BND 60-90 brand bitumen were taken as raw materials in the process of bitumen modification. The percentages of these raw materials are as follows: sulfur -35%, natural rubber -1% to 6%, and bitumen - 59-64%. In studying the chemical properties of modified bitumen, its IR spectrum analysis, MIRA 2 LMU scanning electron microscope, and thermal gravimetric TGA and DTA analyzes were more widely covered. The rheological, wear and high elasticity properties of modified bitumen were analyzed depending on its application. From the results of the analysis, it can be seen that the amount of natural rubber in the modified bitumen content increased, which led to a decrease in the amount of sulfur in the bitumen content. The mechanical properties of bitumen modified with sulfur and natural rubber have reduced elasticity and hardening during cracking. In this research work, it was observed that modified bitumen is resistant to frost, compression, breaking, cracks, and does not lose its original properties and strength for a long time when used in road construction.