The　preparation　of　perovskite　quantum　dots　(PQDs)　using　an　in　situ　inkjet　printing　method　is　beneficial　for　improving　the　problems　of　aggregation　and　photoluminescence　(PL)　quenching　during　long-term　storage.　However,　the　stability　of　PQDs　prepared　using　this　method　is　still　not　ideal,　and　the　morphology　of　in　situ-printed　patterns　needs　to　be　optimized.　To　address　these　problems,　this　study　introduced　polymethyl　methacrylate　(PMMA)　into　the　process　of　in　situ　inkjet　printing　of　PQDs　and　explored　the　effect　of　PMMA　on　the　in　situ　patterning　effect　of　PQDs.　The　results　showed　that　using　a　mixed　precursor　solution　containing　a　small　amount　of　PMMA　as　the　printing　ink　can　slow　down　the　shrinkage　process　of　ink　droplets　and　improve　the　uniformity　of　film　formation.　As　the　printing　substrate,　PMMA　provided　a　suitable　high-viscosity　environment　for　the　in　situ　growth　of　PQDs.　This　could　effectively　suppress　the　coffee　ring　effect.　In　addition,　the　interaction　between　the　C=O=C　group　in　PMMA　and　metal　ion　Pb2+　in　the　CsPbBr3　precursor　molecules　was　favourable　to　enhancing　the　density　of　PQDs.　The　prepared　PMMA-coated　CsPbBr3　quantum　dots　(QDs)　pattern　had　high　stability　and　could　maintain　at　90.08%　PL　intensity　after　1　week　of　exposure　to　air.