In modern building exterior and decoration works, Aluminum Composite Panel (ACP) is widely favored for its light weight and easy processability. Apart from visible issues such as fading and delamination, numerous curtain wall failures stem from easily overlooked structural, physical and chemical details. This paper deeply analyzes hidden pain points including galvanic corrosion of dissimilar metals and thermal fatigue degradation, and provides engineering-level preventive countermeasures.