Abstract: Weisong sympherobiid (Sympherobius weisong Yang) discovered in Hangzhou and Ning County in Zheiiang province in recent years is one of the important natural enemies, which preys both on Matsucoccus matsumurae (Kuwana)and Matsucoccus massonianae Y. & H. It has two generations a year, but no winter diapause. The first generation occurs from April to late November. The second generation occurs from late August to June the following year. The time of its occurrence is well synchronized with that of the scale. The average amount of predation for an adult is 9 pupae or 276.6 eggs per day. A nymph might consume 2837.1 eggs for life time, and it can also prey on the nymph and adult of the scales. Observations indicated that it might exert an obvious suppression on the population of the scales. Experiments showed that its nymph and adult could be reared with eggs or pupae of the scales, eggs of rice moth, a variety of aphids or diet No. Ⅰ.