There is an ongoing debate about whether standards act as trade catalysts or barriers. This article uses a gravity model to analyze the effects of national standards on the trade of agricultural products between China and the 64 Belt and Road (B&R) countries from 1990 to 2019. Mandatory countryspecific standards have positive and significant effects on total trade, exports, and imports. Mandatory international harmonization standards have positive and significant effects on total trade and exports. Voluntary country-specific standards positively (and significantly) affect exports, while voluntary internationally harmonized standards positively (and significantly) affect total trade, exports, and imports. The magnitude of coefficients of mandatory countryspecific standards is the highest, followed by mandatory internationally harmonized standards and voluntary internationally harmonized standards. It is beneficial for China and the B&R countries to strengthen standards cooperation, actively adopt international standards, and evaluate the implementation effect of standards over time.