A theoretical study of the temperature-dependent gain and noise figure effects on erbium-doped fiber amplifiers (EDFAs) pumped at 1480nm is investigated, solving the propagation equations related to two level systems. The solution of these equations is based on the population and temperature difference among amplification levels. The temperature-dependent propagation equation considered is used to determine the gain and noise figure effects on EDFAs. The population difference depends on pump and signal powers, Boltzmann factor K B , cross-sections, noise figure (NF) and Er 3+ concentration. The temperature-dependent gain and noise figure effect the EDFA length are numerically obtained for the temperature range of −20°C to +60°C. All of the analyses consist of the amplified spontaneous emission (ASE) effect.