The temperature dependence of magnetocurrent in the spin-valve transistor has been theoretically explored based on phenomenological model. We find that temperature dependence of the collector current strongly depends on the relative orientation of magnetic moment of ferromagnetic metals due to spin mixing effect.For example,the parallel collector current is decreasing with increasing temperatures,while the anti-parallel collector current is increasing.We then obtain decreasing magnetocurrent with increasing temperatures.The result accords with the experimental data in qualitative manner.Along with this,we find that temperature dependence of hot electron spin polarization can also contribute to the magnetocurrent at finite temperatures.This phenomenological model calculations suggest that it is essential to understand the relative importance of spin mixing effect and hot electron spin polarization in the spin-valve transistor at finite temperatures.