The invention discloses an offshore oil platform floating ice speed in-situ monitoring device which comprises a sea ice imaging platform and an imaging distance automatic adjusting device and further comprises an acoustic water level gauge, a wire arrangement controller, a wire arranging device and guide rods. The in-situ sea ice monitoring device is installed on an offshore oil platform. The device further comprises an offshore monitoring platform and a cable; the wire arrangement controller is connected with the acoustic water level gauge and receives the offshore level change information from the acoustic water level gauge, and the wire arrangement controller is connected with the wire arranging device and used for controlling the number of rotating turns of the wire arranging device to regulate the distance between the sea ice imaging platform and a water surface; and the sea ice imaging platform is penetrated through the two guide rods through sliding holes to enable the sea ice imaging platform to slide up and down in the vertical direction relative to the guide rods. The in-situ monitoring device of the invention can automatically regulate the imaging distance of an imagingdevice along with tidal levels to reduce the error influence brought by the change of the tidal levels and improve the accuracy of floating ice displacement measurement.