Abstract: The scrap collection device of the traditional aluminum foil shearing machine has the problem of uneven suction of the two pipes, which seriously affects the working efficiency.Applying Computational Fluid Dynamics (CFD), we optimized and improved the pipeline baffle structure upon an in-depth analysis on the effect of baffle layout on the branch pipe flow pattern. Suggestion for piping optimization are put forward. Numerical results show: when the heights of the two baffles are equal, the second baffle will "obstruct" the air flow behind the first branch pipe, forming a low-velocity recirculation zone. Thus, negative pressure and suction fail to be formed. The decreasing height of the second baffle reduces the negative pressure and velocity of the second branch pipe, which increases the negative pressure and velocity in the first branch pipe. When the baffle ratio is 1/2, the physical quantities of the two branch pipes tend to be equal, and the difference in the speed of the branch pipe mouth is about 3%. The industrial needs can be met. When changing the baffle height and spacing and keeping the baffle height ratio at 1/2, the speed difference between the two branch pipes is about 5%. It shows that the research results have certain engineering applicability.