Abstract: The material was silkworm after reeling silk.Protein of silkworm ( PSP) was extracted and determined the amino acid and protein pupa molecular weight distribution of PSP. The experimental results showed that, the optimum technological conditions of extracted the PSP was that solid-to-liquid ratio was 1∶3, extraction times were 3, pH was 3.0, in this process the protein extraction rate was 53.0%.Finally, PSP was rich in 18 kinds of amino acids and amino acids content conform to the provisions of high quality protein standards of the FAO/WHO, and the molecular weight distribution from 500～100000u. The silkworm protein after purification would be further used in some fields likes pharmaceutical, food and cosmetics and so on.