The invention provides a blade and a lawn mower. The blade comprises a flat middle portion, and two end portions respectively disposed at two opposite ends of the middle portion, wherein a cutting edge is located on the end portion, and wherein each end portion includes a first end portion and a second end portion, and wherein the second end portion is located between the middle portion and the first end portion, and wherein along the longitudinal direction of the middle portion, the ratio of the length of the first end portion to the length of the blade in a horizontal plane is between 0.045 and 0.09. The blade and the lawn mower have advantages that grass can be smashed completely by the blade to achieve an optimal grass smashing effect, the structure is simple and the cost is low.