This study aimed to primarily analyze the components and physicochemical indexes of the essential oil of fresh onion leaf collected from Kinh Mon District, Hai Duong Province. By GC-MS method, 39 components in the essential oil of fresh onion leaf have been identified. In which, there are ten out of them were hydrocarbons (such as monoterpenes 11.58%, sesquiterpenes 4.02%) and the rest were oxygenated ones (like aldehydes 14.87%, alcohols 45.64%, ketones 4.43%, esters 1.24%, acid 1.37%, oxide 1.69% and others 13.36%). The density of essential oil was 0.82, the acid index was 0.67 (mgKOH\g) and the ester index was 0.74 (mgKOH\g).