The embodiments of the invention disclose a seatbelt detection method and a seatbelt detection device. The method comprises the following steps: acquiring a shot image of the vehicle running condition on a road; performing vehicle detection on the image; segmenting out a vehicle image area; detecting a window area from the vehicle image area, and detecting a face area and/or a steering wheel area from the window area; determining a seatbelt detection area based on the face area and/or the steering wheel area; and extracting a line segment from the seatbelt detection area, and determining whether there is a seatbelt contained in the seatbelt detection area based on the line segment extracted. An intelligent, automatic and efficient seatbelt detection process is realized.