In the past few decades, trap emission was always believed hardly manipulated to luminescent quantum dots (QDs). Actually, not all trap emissions are useless. This work shows that the interface between MnSe dopant and ZnSe host could be used for manipulating irradiative defects with a controllable manner. This study focuses on three basic challenges for manipulating interface defects, including (i) how to introduce irradiative defects at the dopant-host interface, (ii) how to control the intensity of the interface trap emission, and (iii) how to tune QD emission color via the interface trap emission. Finally, this study shows the application of dopant-host interface defects in ratiometric optical thermometry.