Here, a novel transformed CdO with low coordination and N doping environment was simply synthesized through the involvement of the target molecule tetracycline (TC). The results showed that the shedding of surface hydroxyl groups led to a low coordination environment, and N doping formed a new doping energy level, which increased the charge density and promoted the migration and separation of photo-generated carriers. Its photocatalytic performance was 4.32 times higher than that of hydroxy-rich CdO and the selectivity coefficient was 4.8. Combined with theoretical calculation and in situ Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) analysis, the significant improvement of selectivity was due to the interaction of the doped N atom with the methyl carbon in TC. This work provided a new idea for the simultaneous construction of low coordination environment and N-doped materials for efficient selective photocatalysis.