A case heat dissipation unit of handheld electronic device includes a back cover including a ceramic layer. A titanium metal layer or a stainless steel metal layer is disposed on the ceramic layer in a position corresponding to at least one heat source. The ceramic layer is an outer surface of the handheld electronic device and exposed to an external environment. The titanium metal layer or the stainless steel metal layer faces a receiving space of the handheld electronic device in contact with the heat source in the receiving space. The titanium metal layer or the stainless steel metal layer serves to absorb the heat generated by the heat source and transfer the heat to the ceramic layer for dissipating the heat.