This paper focuses on a novel microbial polysaccharide as the research subject, using the high-temperature and high-salinity conditions of the Shengli Oilfield's heavy oil reservoir as the basis for experimental design. Based on Micro-CT scanning results, the QSGS technique was employed to design the channel patterns of the microscopic model, and a microfluidic model for experiments was fabricated using wet etching combined with surface modification methods. Microbial polysaccharide micro-displacement experiments were conducted in high-temperature environments to capture overall images and microscopic phenomena at various displacement stages, thereby evaluating the micro-oil displacement effectiveness of the polysaccharide system in high-temperature and high-salinity heavy oil reservoirs. The study demonstrates that the novel microbial polysaccharide exhibits excellent temperature and salt resistance, maintaining high viscoelastic properties under reservoir conditions of 86°C and salinity exceeding 49,000 mg/L, significantly outperforming xanthan gum and meeting the requirements for injection agents in high-temperature and high-salinity reservoirs. Under microscopic conditions, the novel polysaccharide can mobilize more clustered residual oil, which gradually transforms into porous residual oil and further into droplet-like residual oil during the displacement process, enhancing the displacement efficiency by 10.15% on top of water flooding, which is 3.08% higher than that of xanthan gum. As a pure biological agent, the novel microbial polysaccharide shows promising temperature and salt resistance along with effective performance, indicating its potential application in high-temperature and high-salinity reservoirs and providing a viable technical approach for enhancing oil recovery in such environments.