The layout of shelves in the storage center is one of the important factors affecting the efficiency of picking operation. In order to study the impact of layout of shelves on the effective storage area, the Fishbone layout is chosen as the research object, an estimation model of the proportion of effective storage area is constructed and verified by simulation. The results show that when the angle of the main picking channel is fixed, the larger the ratio of the picking channel width to the shelf width, the smaller the utilization of the effective storage area, when the ratio of the picking channel width to the shelf width is fixed, the more the angle of the main picking channel approaches 0 degree or 90 degrees, the greater the utilization of the effective storage area. Therefore, the improved storage layout such as the Fishbone layout provides a new way for decision-making in picking operation, and also proves the feasibility of the practical application of the improved storage warehouse layout.