An embodiment of the invention discloses a parking space detection method based on an ultrasonic radar, and is applied to parking space detection. The method includes by a terminal, acquiring echo signals received by the ultrasonic radar at a plurality of moments, wherein the echo signals are signals of the configured terminal, which are reflected by obstacles during the movement of vehicles relative to the obstacles; by the terminal, constructing a coordinate system of a parking space; by the terminal, dividing the parking space into a plurality of spatial units in the coordinate system; by the terminal, determining projection lines of possible distribution areas of the obstacles in the coordinate system according to the echo signals; by the terminal, counting the number of the projectionlines included in the first spatial unit, wherein the first spatial unit is any one of the spatial units; when the number of the projection lines included in the first spatial unit is greater than apreset threshold, by the terminal, determining that the first spatial unit is a spatial unit that includes the outlines of the obstacles; by the terminal, determining the parking space size accordingto the first spatial unit.