The outbreak of COVID-19 has led to the growth of global cross-border e-commerce by 2-10 times higher than the historical rate，and cross-border e-commerce retailing （B2C） has entered a golden period of growth. In order to increase fiscal revenue and regular the e-commerce，developed economics have launched the related rules about taxation and customs clearance facilitation，and China’s cross-border e-commerce retailing is faced with a more complex international environment. To keep the advantage of China’s cross-border e-commerce retailing in international market，on the basis of collecting the evolution of China’s cross-border e-commerce “postal parcel” rules，this report selects the United States and Canada which are representative of “Liberalism”，and the European Union and the United Kingdom which are representative of “Protectionism” for comparative analysis. By summarizing the advanced rules taken by developed countries in Europe and American and combining the provisions of the regional trade agreements on cross-border e-commerce “postal parcel”，this report suggest that China should keep the manufacturing advantage of low-value goods in the Pearl River Delta region and strengthen the brand awareness；improve the efficiency of customs clearance in the RCEP and other trade agreements，to give more low-value goods to the contracting party’s duty-free and domestic tax preferential policies for keeping open the domestic market.