Inertial confinement fusion (ICF) mainly uses strong focus laser beams to irradiate the target to obtain sufficient energy. The ignition target is an essential factor for inducing a fusion reaction within a capsule. The cooling arm that connects the cooling source to the hohlraum is an important part of the ignition target, which is used to obtain an accurate and uniform temperature field for the deuterium-tritium ice pellet. To improve the temperature uniformity of the connecting surfaces between the cooling arm and the hohlraum, the cooling arm is designed to have a groove structure. On the basis of theoretical analysis and temperature simulation, the three-branch cooling arm was found to have a smaller temperature difference on the clamping surface and better mechanical strength than the cooling arm with fewer branches. Moreover, the fracture failure test shows that the fracture force of the three-branch cooling arm is 1.12 N, which is larger than that of the two-branch cooling arm. Because the smoothness of the connecting surface between the cooling arm and the hohlraum has a considerable effect on heat transfer, a KOH:isopropanol (IPA) solution is used to polish the rough deep reactive ion etching (DRIE) surface.