Silica (SiO₂) thin films have enormous potential for applications in semiconductor devices, integrated circuits, optical coatings, and other fields due to their excellent optical properties. However, the preparation process of SiO₂ thin films faces some issues such as surface roughness, impurity control, and compactness. To address these issues, researchers have improved the performance of SiO₂ thin films through process improvements and surface modifications. Among the many techniques for preparing SiO₂ thin films, plasma enhanced chemical vapor deposition (PECVD) has become the most commonly used method for preparing SiO₂ thin films due to its advantages such as low temperature required for deposition and in-situ growth. This article reviews the development of preparing SiO₂ thin films using PECVD technology, and explores the influence of key process parameters and post-treatment processes on the quality of the films. The in-depth study of PECVD technology helps to achieve more precise control of SiO₂ film growth and further expand its broad application prospects.