Amplified spontaneous emission (ASE) sources based on erbium- doped fibers are widely applied in many fields, such as fiber sensing, communication and precision measurement. It plays a negative role of light noise after a process of long- term continuous operation to precision and sensitivity of the following detection and measurement systems. However, it has been reported rarely. Here, via accelerated aging experiment at 343 K, the light noise of optical section of ASE is studied. During the process, optical noise is detected in- situ. According to Arrhenius model, in the early stage of 3200 h at room temperature, the optical noise decreases about 0.0743 μV2Hz-1 then slowly increases about 0.0338 μV2Hz-1 in latter stage of 44416 h. Before and after acceleration aging, optical noise is a quadratic function of optical power. By fitting, it is obtained the second order item coefficient α , or termed as to coefficient of relative intensity noise, and the first order item coefficient β , or termed as to coefficient of shot noise. Through the aging, both of them increase, where α and β increase 0.010 μV2μW-2Hz-1 and 0.054 μV2μW-1Hz-1 , inceptively. Moreover, the spectral shape of ASE is irrecoverably shifted after accelerated aging.