This work investigates the effect of ambient conditions on jet-A spray combustion in an optical constant volume combustion chamber. Based on the data of jet-A and diesel fuel data obtained from previous experiments, a comparison between jet-A and diesel was conducted in terms of spatially integrated flame intensity, flame area, and flame intensity per pixel. Trasient and quasi-steady state analyses were carried out in this work. The transient analysis was conducted using high-speed imaging of both OH∗ chemiluminescence and natural luminosity (NL). For quasi-steady state analysis, three emissions (OH∗, narrow-band flame emission at 430nm (Band A) and at 470 nm (Band B)) were captured using an ICCD camera. From the transient analysis, jet-A flame shares a similar trend of flame development to diesel flame during the entire combustion process, featuring a narrow region of NL and a wide region of OH∗ with the increase of ambient temperature and O2 concentration. The soot is oxidized more quickly for jet-A at the end of combustion by comparing the area of NL, especially under high O2 concentration condition. From the quasi-steady state results compared to the ones of diesel flame, intensity of OH∗ is higher for jet-A under low O2 concentration but lower under high O2 concentration; intensity of NL is higher for jet-A in all the experimental conditions, but the intensities of Band A and Band B are lower for jet-A in most experimental conditions.