Excimer pumped sodium laser has the potential to realize the sodium beacon light source. During the operation of the laser, excimer is utilized to pump sodium atom from ground state to excited state, so it is necessary to experimentally study the fluorescence lifetime of excited sodium atom produced from dissociation of excimer pairs. In this work, sodium-ethane excimer pairs are excited by blue satellite pumping light with different wavelengths, and the fluorescence lifetimes of sodium D1 and D2 lines are measured at different operation temperatures. The experiment results demonstrate that the fluorescence lifetimes of 32P3/2 and 32P1/2 states are obviously longer than their natural lifetimes, the longer the excitation wavelength, the more obvious the extended fluorescence lifetime. Radiation trapping effect is considered as another factor that leads to the fluorescence lifetime lengthening. On the other hand, as the single photon energy decreasing, the probability of excimer pairs excited to A2Π3/2 state increases, and the excited sodium atom can be produced during a longer period, and this may also lead to the fluorescence lifetime lengthening. For sodium-ethane excimer pairs, the amplification characteristic of sodium D2 line amplified spontaneous emission signal is better than that of sodium D1 line. The better amplification characteristic and longer fluorescence lifetime make sodium D2 line laser easier to achieve.