Multifunctional detection device and continuous positioning detection method for drainage box culvert

The invention relates to a multifunctional detection device for a drainage box culvert, which comprises a telescopic rod, a support rod and a connecting frame, the telescopic rod is vertically connected with the top end of the connecting frame, a wireless signal transmitter is fixed at the free end of the telescopic rod, the support rod is axially clamped and fixed on the connecting frame, and the support rod axially extends towards one side of the bottom end of the connecting frame. A three-dimensional laser scanner, a lighting and camera shooting assembly, a laser range finder and a control switch are arranged on the connecting frame, and the three-dimensional laser scanner, the lighting and camera shooting assembly and the laser range finder are sequentially arranged from high to low in the direction away from the supporting rod; the control switch simultaneously controls the opening and closing of the three-dimensional laser scanner, the illumination camera assembly, the laser range finder and the wireles