The invention provides a determination method and device for re-detecting a ground. The method comprises the steps that if a gravity acceleration vector of a current image frame acquired from collecting equipment changes relative to a gravity acceleration vector of a last image frame, an identification of the current image frame is set; according to the number of set identifications of a continuous image frame, it is judged whether or not the acquisition equipment tends to be stable after moving; if yes, the similarity between the gravity acceleration vector of the current image frame and a ground normal vector corresponding to a current ground equation is determined; and if the similarity is less than a similarity threshold, it is determined that the ground needs to be re-detected. According to the determination method and device for re-detecting the ground, it is determined whether or not the equipment tends to be stable after moving through the changing times of the gravity acceleration vector of the continuous image frame, if yes, it is determined whether or not the ground is re-detected by using the similarity between the gravity acceleration vector of the current image frameand a ground method vector corresponding to the ground equation, the vibration disturb of the equipment can be filtered out, when an view angle or posture of the equipment change, the re-detection isaccurately grasped, and it is ensured that the accurate ground is outputted.