As the representative of governmental translation institutions in late imperial China, the translation department of the Jiangnan Arsenal played a fundamental role in the process of bringing in western science and technology and enlightening the society. It had formed a series of translation methods during a mass of western scientific translation practices. On the one hand, the translation department made the method of combination of oral translating and transcribing to the zenith which had a long history within translation field in China. On the other hand, it had created relatively reasonable translating rules, especially the rules of scientific nomenclature. Among them, considerable production of nomenclature translation has all along been in use up to now. In addition, the translation department of the Jiangnan Arsenal also paid much attention to the compilation of vocabulary of terms or names related with various subjects. Later, such work became a great contribution to the unification of scientific nomenclature in China. Nevertheless we can also find some inevitable deficiencies of above-mentioned translation methods which resulted in a large number of errors in the publications of the Jiangnan Arsenal.