This paper studies the sources and usefulness of Wugou, Qingou and Jingou through the analysis for the related documents. The research results show that Wugou was actually a kind of brone hook made in Wu Country of the Spring and Autumn Period and also named as gold hook. It was originally a kind of adornment worn by the ruling class and never used as a weapon. However, people could not know this lost article for a long time and they could only find it in some poems. In the excavation in No. one pit of the terracotta soldiers and houses of Qin Dynasty, two hooks were found and people were puzzled for whether they are Wugou or Jingou. The author in this paper thinks that they should be Qingou(hook made in Qin Dynasty), because they were used in Qin Dynasty and excavated in the relics of Qin Dynasty.