Solution　processable　hybrid　perovskite　film　and　quantum　dots　(QDs)　have　shown　promising　application　in　optoelectronic　devices　owing　to　their　inherent　crystal　structures,　ionics　property,　and　electronic　nature.　The　manipulation　of　halide　anions,　for　both　perovskite　bulks　and　quantum　dots,　is　definitely　critical　for　rendering　such　materials　with　peculiar　optoelectronic　characteristics.　Herein,　the　tunable　emissions　at　the　solid　interface　between　CH3NH3PbI3　film　and　CsPbBr3　quantum　dots　via　halide　anion　exchange　are　reported.　By　in　situ　photoluminescence　and　X-ray　diffraction　measurements,　the　gradual　substitution　of　Br　ions　in　the　CsPbBr3　QDs　lattice　by　I　ions　in　CH3NH3PbI3　film　and　the　reversed　ions　exchange　process　is　elaborately　monitored,　respectively.　In　addition,　the　morphology　of　CsPbBr3　QDs　on　CH3NH3PbI3　film　and　micronet　is　preserved　according　to　atomic　force　microscope　and　high-magnification　scanning　electron　microscope　observations.　Furthermore,　the　time　course　of　the　anion　exchange　can　be　tuned　by　tailoring　the　density　of　ligands　on　CsPbBr3　QDs.　By　exquisite　manipulation　of　halide　anions　exchange,　capability　is　achieved　to　tailor　the　emission　color　continuously　at　the　microscale.　This　work　expands　the　understanding　of　perovskite　anion　exchange　to　new　dimensions　and　implies　their　potential　applications　in　optoelectronic　devices　owing　to　the　gradient　energy　level　stem　from　the　interfacial　transition.　Copyright　©　2018　American　Chemical　Society.