According to the requirements of a coronagraph for suppressing the stray light in Solar Polar Orbit Radio Telescope Mission, a toothed occulter for the coronagraph was designed to suppress the diffracted light in a higher level. The diffracted light distribution from the toothed occulter was calculated by using the semi-infinite rectangle method, and an optimized shape with the lowest diffracted light was obtained. Meanwhile, the stray light level of the optimized toothed occulter was measured experimentally, and the obtained result was compared with the diffraction intensity of a round disk occulter. It verifies that the toothed occulter has an advantage over the round disk in diffracted light reduction. The measured data show that the suppression of diffracted light of the proposed toothed occulter has been up to 10-7 level after optimization, higher than internationally 10-6 level in the lab. The suppression level has been met the demands of large view coronagraphs.