A hand push lawn mower includes a body including a cutting blade and an operating device for a user to operate and connected to the body. The body includes a deck, a motor, a height adjustment assembly and a grass baffle. The motor is configured to drive the cutting blade to rotate. The height adjustment assembly is used to adjust the deck to move up and down. The grass baffle is configured to prevent grass clippings from splashing towards the back of the hand push lawn mower. When the height adjustment assembly adjusts the height of the deck, a displacement of the grass baffle in a vertical direction is less than a displacement of the deck in the vertical direction.