Recently, as the application range of high-end Organic Light Emitting Diodes (OLED) displays has expanded, the pixel area has become larger and panel architecture complexity has been raised to increase the lifespan and efficiency of the panel. At the same time, the remaining moisture in the organic material of the panel increases, and pixel shrinkage defects in which the pixel edge emission area is reduced by cathode oxidation due to moisture diffusion within the panel are increasing. Therefore time and cost are incurred in the process of design and manufacturing process enhancing to improve reliability of the display panel. In this study, we introduce an analysis model that can quantify pixel shrinkage and predict the occurrence of defects in advance. In order to make up for the shortcomings of existing Finite Element Method (FEM) and numerical analysis models, product design specifications were applied through layout-based 3D geometry, and the degree of curing according to the heat treatment conditions of organic materials was calculated and the physics of moisture diffusion between subsequent cleaning and oven process were also applied in the model. The degree of moisture absorption during the waiting time between processes, one of the main factors affecting defects was applied in connection with the curing rate of organic materials. In addition, the residual concentration after moisture diffusion in the final deposition process was quantified and matched with the actual shrinkage defect occurrence level to optimize design and process factors of the model. As a result of verification based on 20 evaluation models, the consistency of about 0.96 based on R2 was confirmed.