A high sensitivity $D$-shaped hole double-cladding fiber temperature sensor based on surface plasmon resonance (SPR) is designed and investigated by a full-vector finite element method. Within the $D$-shaped hole double-cladding fiber, the hollow $D$-section is coated with gold film and then injected in a high thermo-optic coefficient liquid to realize the high temperature sensitivity for the fiber SPR temperature sensor. The numerical simulation results show that the peaking loss of the $D$-shaped hole double-cladding fiber SPR is hugely influenced by the distance between the $D$-shaped hole and fiber core and by the thickness of the gold film, but the temperature sensitivity is almost insensitive to the above parameters. When the thermo-optic coefficient is $2.8\times {10}^4/°\mathrm{C}$, the thickness of the gold film is 47 nm, and the distance between the $D$-shaped hole and fiber core is 5 μm, the temperature sensitivity of the $D$-shaped hole fiber SPR sensor can reach to $3.635\mathrm{nm}/°\mathrm{C}$.