The principle of public order and good customs, enshrined in Articles 8 and 153 of China's Civil Code, serves as a foundational mechanism to invalidate civil acts that contravene societal morals and public interests. This paper examines its judicial application through analysis of recent court cases from various provinces, highlighting inconsistencies in interpretation and enforcement. Drawing from specific judgments, it identifies issues such as arbitrary citation of principle-based versus rule-based clauses, leading to divergent outcomes in similar disputes. The study proposes normative measures, including Supreme People's Court (SPC)interpretations and case guidance, to enhance uniformity and predictability in adjudication. By addressing these challenges, the principle can better safeguard social harmony while respecting legal certainty.