The invention relates to a seed dividing head of a planter, which is arranged in the centre of a seed dividing conduit. The lower part of the seed dividing head is provided with a seed dividing frustum. The centre at the bottom of the seed dividing frustum is provided with a screwed hole, and the screwed hole is connected with a direct current electric motor of which the power is provided by the seed dividing head. The upper part of the seed dividing frustum is provided with a cylindrical seed dividing body. The upper surface of the seed dividing body is provided with a secondary seed dividing touch plane, and the centre of the secondary seed dividing touch plane is provided with a cone round rod. A seed ranking tube is sleeved at the top of the cone round rod. The secondary seed dividingtouch plane is provided with two symmetrical seed dividing bosses, and both seed dividing planes of each seed dividing boss are perpendicular to the secondary seed dividing touch plane. In the invention, the cone and a section plate form a first-class seed dividing structure, and the cone round rod and the seed dividing touch planes surrounding the cone round rod form the secondary seed dividing structure. The invention improves the uniformity and the stability of seed division and changes the vibration caused by the gravity centre shift of the traditional seed dividing head. The accuracy andthe scientific performance of the contrast test research in small area fields are improved.