Embodiments of the present application relate to the field of ground detection, and disclose a ground detection device, a robot and a ground detection method. The ground detection device includes a control circuit, a signal trigger circuit, a signal sampling circuit and an amplification circuit. Where, the signal sampling circuit is configured to acquire reflected light of the optical signal reflected by a detection area and ambient interference light, and to generate a second voltage signal according to the reflected light and the ambient interference light; the amplification circuit is configured to amplify the second voltage signal to acquire a third voltage signal; and the control circuit is configured to compare the third voltage signal with a preset voltage, and to determine whether there is a ground within the detection area according to a comparison result.