The invention relates to a simple detection ruler for the gradient of a structural column. The simple detection ruler comprises a lower vertical ruler, an upper vertical ruler, a vertical ruler connector, a clamping groove base, a clamping groove, a transverse ruler and a plumbline, and is characterized in that the vertical ruler connector is welded to the lower vertical ruler; a first nut set and a second nut set are fixed to the two ends of the upper vertical ruler respectively; the lower vertical ruler is connected with the upper vertical ruler through the vertical ruler connector and the first nut set; the clamping groove base is fixed on the upper vertical ruler through the second nut set; the clamping groove is vertically welded to the clamping groove base; the transverse ruler is inserted into the clamping groove and is fixed with a third nut set arranged on the clamping groove; the transverse ruler can freely move in the clamping groove in the horizontal direction; the plumbline is fixed on the transverse ruler. The simple detection ruler has the advantages of being convenient to carry, simplifying the detection method, improving the efficiency and precision and reducing workloads.