As a core technology for ionizing radiation detection, the performance of scintillation detectors has improved significantly over the past few decades, and their key components, such as scintillators and photodetectors, have also undergone multiple iterations. However, little attention has been paid to the fact that, besides the intrinsic properties of materials and the quantum efficiency of photodetectors, the assembly matching between components also plays a decisive role in the overall performance of the detector, as reflected in improved light collection efficiency (LCE). Therefore, a systematic investigation into the influence of assembly optimization on LCE is of great significance for promoting the development of high-performance scintillation detectors. This paper first defines the concept of LCE and clarifies its influence on the key performance of scintillation detectors. Subsequently, focusing on assembly optimization, it outlines improvements in LCE through multi-interface optical synergy among scintillators, reflective layers and coupling media. Finally, the effective conversion of collected photons into measurable electrical signals is promoted through rational photodetector matching, thereby further improving the overall detection efficiency of scintillation detection systems. In addition, the emerging role of AI-assisted design in scintillation-detector assembly optimization is discussed as a forward-looking perspective. This review systematically summarizes and compares LCE-enhancement strategies at the assembly level, extracts transferable design guidelines from different optimization approaches, and outlines a possible future workflow for AI-assisted assembly optimization.