The uncorrelated energy of negatively charged trion confined in a semiconductor cylindrical quantum dot (QD) under temperature effect is theoretically investigated using a variational procedure within the effective mass approximation. We have used a wave function satisfying for the strong confinement regime and also presenting well results for the weak confinement regimes. The trion confinement is described by a finite and infinite square potential wells under the temperature effect. Our findings show that the uncorrelated energy of the negatively charged trion is more important for the small size of the QD. We have found a strong dependence of negatively charged trion energy on the confinement potential. Besides, our numerical results have shown that the effect of temperature leads to an increase in uncorrelated energy. The temperature has a significant effect on the stability of the three non-bound charge carriers.