Abstract: The prosperity of the agricultural development heyday was Qing Dynasty before 1840. Yang Shen, a leader majored in sericulture, had made lots of contributions to development of agriculture in Shaanxi Guanzhong region. But the view he hold that cereal crop and mulberry should be coexistence did not last development. In this paper, with Yang Shen’s view as the starting point, summarize the characteristics of this period Guanzhong sideline development, which means from Sericulture to Cotton Planting. Respectively, trying to from the conditions for the development of cotton and mulberry proceed, also a comprehensive analysis of the reasons for the change of the Qing Dynasty between the cotton and the mulberry relationship with multiple angles. The final conclusion was that Yang Shen’s view was only feasibility under the prevailing social, economic and technological conditions, while it ultimately failed because of the inevitability of the historical development.