Partial discharge (PD) serves as an early warning signal for the deterioration of cable insulation, often associated with construction defects in cable intermediate joints. This paper examines five common types of latent defects found in 10 kV cable intermediate joints. Through a combination of finite element simulation and experimental testing, we systematically investigate how these defects’ type, size, and location influence electric field distortion and partial discharge characteristics. The findings indicate that interfacial gap defects result in a high electric field concentration at their tips, leading to significant field distortion and local discharge effects. In contrast, the maximum electric field intensity associated with burr defects and interfacial impurity defects is lower. However, these defects can also trigger considerable local discharge due to their higher field distortion rates. The results of this research provide a theoretical basis for optimizing the installation process of intermediate joints and for conducting online monitoring of partial discharge.