We analyze spin-dependent transport through a spin-diode in the presence of spin-flip and under influence of temperature bias. The current polarization and the spin accumulation are investigated in detail by means of reduced density matrix. Results show that the spin accumulation is linearly increased when the metallic electrode is warmer whereas, its behavior is more complicated when the ferromagnetic lead is warmer. Spin-flip causes that the current polarization becomes not only a function of spin-flip rate but also a function of temperature. The current polarization is reduced up to 90% if the time of spin-flip is equal to the tunneling time. The behavior of spin-dependent current is also studied as a function of temperature, spin-flip rate, and polarization.