1. According to the picking location, it is divided into house swallow and cave swallow. Cave swallows were picked in caves, but now they are gradually replaced by domestic swallows because of the scarcity of production and the growing voice of environmental protection. The swallow was picked at home. Jin Siyan is still wild. It goes out for food in the morning and comes back at night.

2. According to the edible degree of bird's nest, it is divided into Jin Siyan, Cao Yan and Mao Yan. Jin Siyan is the edible bird's nest after cleaning. Caoyan and Maoyan are non-Swift nests in Jin Siyan, and their bird's nests have few contents and cannot be eaten. Wool bird's nest is an unwashed bird's nest, which can be eaten after washing.

3. According to the shape of bird's nest, it can be divided into swallow lanterns, strips, pieces, cakes, horns and nets. The first three types are classified according to the degree of damage after picking and transportation. Yan cake is made of processed and pressed. Yanjiao is the bottom adhesive part of the nest on the wall of Jin Siyan. It tastes delicious. White swallow net is a fine net that supports eggs and Xiaoyan in the middle of bird's nest, and its taste is delicate and smooth.

4. In addition, they are divided into Bai Yan, Blood Swallow and Yellow Swallow by color. Blood swallow is not the result of Jin Siyan vomiting blood, because red hemoglobin will only be oxidized to dark brown methemoglobin.