0.3%。 Guard ring is usually used in the traditional cell wheel feed. Because of the relative movement and rub between the seeds and the guard ring, it will cause the damage of seeds and the wear and tear of the inner face of guard ring and the outer face of cell wheel. A disassemble rubber guard device was developed and the rubber guard tape could rotate with the cell wheel simultaneously. The rate of damaged seeds and the wear and tear of the outer face of cell wheel decreased significantly because there was no relative movement between the seeds and the rubber guard tape. The construct of the disassemble rubber guard device and the material, shape, strength and length of rubber guard tape were optimum designed. The disassemble rubber guard device was installed on the precision rice hill-drop drilling machine. The test results in laboratory and in field showed that the rate of damaged seeds is less than 0.3%.