I will present our recent results on mid-infrared selected active galactic nuclei (AGNs). We derived their stellar masses, star formation rates, dust properties, AGN contributions, as well as obscurations by fitting their optical to far-infrared photometry through the state-of-art spectral energy distribution (SED) technique. Our obscured AGNs by infrared selection are not significant different from the star-forming sequence. We confirm our previous finding about compact host galaxies of obscured AGNs at z~1, and find that galaxies with 20-50% AGN contributions tend to have smaller sizes, by~25-50%. Besides, we show that high merger fraction up to 0.5 happens to the most luminous (LIR ~46 ergs/s) AGN host and non-AGN galaxies, but not to the whole obscured AGN sample. Moreover, merger fraction has dependence on the total and star-forming infrared luminosity, rather than the decomposed AGN infrared luminosity. Our results suggest that major merger is not the main driver of AGN activities, and obscured AGNs might be triggered by internal mechanisms, such as secular process, disk instabilities, and compaction in a particular evolutionary stage. I will also discuss the role of environment on these obscured AGNs, based on new data from JCMT Large Programs.