Protecting labour rights is an important approach to shaping the new advantages of trade competition and achieving high-quality development of China’s export trade. This paper considers SA8000 certification as the criterion for labour rights protection and manually collects information from firms certified by the National Certification and Accreditation Administration of China. Next, we investigate the effects of SA8000 certification on firm exports. The results show that SA8000 certification significantly expands the export scale while improving export quality. The mechanism analysis shows that the improvement effects are achieved in three ways: reducing operating costs, improving social reputation and increasing labour efficiency. Moreover, the positive effects of SA8000 certification are more profound for resource-intensive firms, non-state-owned firms and large firms. Our study provides an important reference for safeguarding labour rights and reconstructing new competitive advantages in exports.