A burner of a gas stove includes a burner body, a partition member, and at least one flame cover. The burner body includes an inlet portion and a base. The inlet portion has at least one inlet passage for injecting gas and air, and the base has at least one mixture passage for mixing the gas and the air. The at least one mixture passage communicates with the at least one inlet passage. The partition member has a plurality of through holes and covers the at least one mixture passage. The at least one flame cover has a plurality of flame holes and covers the partition member. Whereby, the size of the burner of the gas stove could be reduced significantly, and the gas could mix with the air effectively and uniformly.