The invention discloses a reusable carrier rocket vertical soft landing guidance method based on sliding mode control, and the method comprises the following steps: 1, building a mathematical model with a pseudo height variable tau as an independent variable, 2, designing a guidance law, and 3, obtaining real-time parameters of an aircraft through a missile-borne sensor, 4, inputting the instruction into an actuator, and controlling the flight of the aircraft; and step 5, repeating the step 3 to the step 4 until the rocket vertically and softly lands. According to the method, the sliding mode control theory is used for whole-process guidance of vertical landing of the rocket, various constraints such as fuel are considered, and external conditions such as large space span in the rocket returning process, different tasks in various flight stages, complex and variable flight environments and relatively strong uncertainty interference are overcome; the speed error, the position error and the falling angle error of the rocket during landing are enabled to approach to zero, and vertical soft landing of the rocket is realized.