Views of scholars of china and foreign are different about the lawful nature of the bill of lading. An attempt was made to argument the view of the nature of title of the bill of lading. The definition of the bill of lading was given and the lawful features were discussed: One is evidence of the contract of carriage of goods by sea; Two is evidence of the taking over or loading of the goods by the carrier; Three is undertakers to deliver the goods against surrendering the bill of lading. Then, the lawful nature of the bill of lading, i.e., the nature of title, was discussed. Furthermore, three reasons were summarized through historical and realistic analysis: First, the generation of the nature of title of the bill of lading has historical reason; Second, the nature of title of the bill of lading comes up to the commercial needs; Third, that the bill of lading can be negotiated decides that the bill of lading has the nature of title. In addition, the article emphasizes that the nature of title of the bill of lading has some limitations.