Interest in simulation and modeling techniques in the pharmaceutical industry has grown drastically in recent years. These techniques have improved our understanding of the fundamental pharmaceutical processes by providing valuable insights into the manufacturing processes. This review focused on mechanism-based modeling and its application in simulating intermediate quality attributes and drug product quality for pharmaceutical unit operations related to granulation and compression process. On the basis of the mechanism, granulation is categorized as wet and dry. Various mathematical modeling principles and case studies were introduced with predictive values and intermediate quality attributes of drug product. Modeling techniques used to predict drug quality in a pharmaceutical unit operation can be classified into two categories: empirical models and mechanism-based models. According to the Food and Drug Administration-mandated Quality by Design (QbD) concept, the use of proper modeling can help determine the effect of process parameters on product quality and establish scale-up strategies for commercial processes. Consequently, Mechanism-based modeling provides valuable insights into the manufacturing process, which can result in improvements in the pharmaceutical continuous manufacturing process.