The extension of impervious surface serves as a key indicator of urbanization and environmental quality. This paper explores the integrated use of Landsat imagery and nighttime light (NTL) imagery for impervious surface mapping. An optical and NTL based spectral mixture analysis (ON_SMA) at sub-pixel level is proposed where local endmembers are used and adaptive endmember sets are selected based on the information provided by both sensors. Results illustrate that comparing with optical based spectral mixture analysis, the proposed approach yields effective improvement in impervious surface detection due to the contribution of the NTL data. The findings highlight the potential of combining optical and NTL data for earth observation, which provide opportunities for new applications.