Below elbow amputee children face many difficulties in wearing prostheses: they grow up quickly and face replacement problems, causing economic burdens. Even remote areas lack professional channels to obtain prostheses, and prosthetic functions are insufficient. Therefore, we designed HanDo to solve the difficulties of children with severed limbs. HanDo is a prosthetic designed for below elbow amputee children from 6 to 12 years old. Through 3D printing and modular design, parts can be replaced independently, which can solve the economic problems caused by frequent replacement of entire prostheses. HanDo has the grasping function, and extended kits to assist living, learning and sports needs. In addition, children can replace the HanDo shells they like, so they can be more confident, healthy and happy. Now the team is still working on therapeutic applications and online services. We hope to make the prosthetic services far-reaching.