Abstract: It is inevitable that there is loss of precious metals during the jewelry manufacturing procedure, and the rate of loss would greatly affect the efficiency of the factory.In order to control the rate of loss, it is necessary to analyse what causes the loss of precious metals.Through the extensive survey of the loss in the jewelry manufacturing procedure, it is found that there are many reasons causing the loss, which could be summarized as three main aspects in this paper.The first one is caused by the manufacturing process, which mainly happens in the processes such as melting, pouring, grinding, polishing, etc.The second one is caused by the deficit of precious metals for the lowest karat requirement, and the third one is caused by material losing or stealing.The loss reasons of precious metals are analysed in order to establish a foundation for the jewelry factories to set up the reliable material management rules, the perfect recovery system and the tight precaution system.