The invention relates to a standard ellipse plotting instrument. According to the solving scheme, the standard ellipse plotting instrument comprises a bottom plate. Two positioning blocks are installed on the bottom plate. Blind holes are vertically formed in the positioning blocks. Cylindrical bodies are inserted in the blind holes. Sliding grooves are obliquely formed in the cylindrical surfaces of the cylindrical bodies. Guide hemispheres are fixed to the inner edge surfaces of the blind holes and placed in the sliding grooves. A connecting piece is arranged on the right side of the bottom plate. A follow-up rotor is clamped on the left side face of the connecting piece. A vertically-arranged plotting pen is inserted into the connecting piece. A rope penetrating hole is formed in the left end face of the follow-up rotor. A positioning rope penetrates into the rope penetrating hole. The two ends of the positioning rope penetrate out of the rope penetrating hole to be fixed to the upper portion of the two cylindrical bodies correspondingly. Operation is easy, a standard ellipse graph can be obtained, and in the plotting process, the cylindrical bodies rotate and move up and down, so that the plotting pen and two fixed points are located on the same straight line, the rope is staggered up and down automatically, the left and right positions of the rope are exchanged under the effect of the follow-up rotor, and the fixed points does not block the rope.