An assembled wearable electronic device includes a first body, a second body and an engaging assembly. The first body has a primary system for providing the independent operation of the first body and producing a related first data. The second body has a secondary system and a fixing assembly. The secondary system is for providing the independent operation of the second body and producing a related second data. The engaging assembly is disposed at one of the first and second bodies. When the engaging assembly is located at a first position, the first and second bodies contact each other to be combined through the engaging assembly. When the engaging assembly moves to a second position, the first and second bodies are configured to be separated from each other. When the first and second bodies are connected to each other, the second data is read by the primary system.