To address the needs of reservoir development with complex geological conditions in Shengli Oilfield，this paper systematically elaborates on the independent R&D process，core technologies，and application achievements of reservoir numerical simulation software. Through years of dedicated research，Shengli Oilfield has developed a series of proprietary software，including a 3D three-phase black oil model，as well as compositional numerical simulation software for chemical flooding and CO₂ flooding. These innovations have effectively resolved key technical challenges such as characterizing flow laws at ultra-high water-cut stages and describing the oil displacement mechanisms of novel chemical flooding systems. The software demonstrates significant technical advantages in simulating differentiated oil-water flow at ultra-high water-cut stages and nonlinear flow in low-permeability reservoirs. Furthermore，by establishing efficient mathematical model discretization and solution algorithms，such as decoupling sequencing，alternating direction，adaptive grids，and algebraic multigrid methods，the software achieves rapid solutions for reservoir models with millions to tens of millions of grid cells，largely meeting the needs of field development planning. However，compared to international commercial reservoir simulation software，Shengli Oilfield’s self-developed numerical reservoir simulation software still exhibits gaps in functional completeness，large-scale parallel computing efficiency，and the integration of emerging technologies. To bridge these gaps，further advancements are required in core reservoir simulation technologies，including new development paradigms for integrating modeling and simulation as well as combining multiple recovery methods；CPU + GPU large-scale parallel computing；the integration and application of emerging technologies based on big data and artificial intelligence.Through continuous technological innovation and functional optimization，Shengli Oilfield’s reservoir numerical simulation software will strengthen its competitiveness，providing robust support for the efficient development of complex reservoirs.