All　inorganic　perovskite　quantum　dots　(PeQDs)　of　CsPbX3　(X　=　Cl,　Br,　I,　or　their　mixture)　are　regarded　as　promising　candidates　for　photovoltaics　and　optoelectronic　devices　owing　to　their　excellent　and　unique　optical　and　electronic　properties.　However,　their　inherent　poor　stability　severely　limits　their　practical　applications.　Herein,　aiming　at　improving　their　stability　and　photoluminescence　(PL)　properties,　a　novel　surface　capping　ligand　strategy　was　performed　via　directly　synthesizing　CsPbX3　quantum　dots　(QDs)　by　hot　injection　method　with　straight-chain　n-alkylmonoamine　instead　of　conventional　organic　amine　(oleylamine)　as　ligands.　With　stronger　intermolecular　interaction　and　denser　alignment,　n-alkylmonoamine　ligands　would　form　a　stable　protective　layer　on　the　surface　of　PeQDs.　As　a　result,　the　n-alkylmonoamine　capped　CsPbBr3　QDs　exhibited　remarkable　long-term　storage　with　70%　of　PLQY　retaining　after　30　days　in　the　open　air,　impressive　water　resistance　for　over　1　h　in　water,　significant　photostability　with　hour-scale　laser　exposure,　and　high　thermal　stability　with　60%　of　PLQY　retaining　after　heating　at　80　degrees　C　for　over　60　min.　In　addition,　by　blending　the　CsPbBr3　QDs　with　polymer　as　the　gate　dielectric,　novel　light-erasable　transistor　memories　were　fabricated　based　on　the　device　architecture　of　a　floating-gate　transistor　memory　(FGOTM).　Acting　as　dense　charge　tunneling　layers　for　charge　trapping　materials　(PeQDs)　in　light-erasable　transistor　memory,　the　alkylmonoamine　ligand　layers　led　to　significant　broadening　of　memory　windows,　presenting　various　charge　capture　abilities　of　the　PeQDs　with　the　different　capping　ligands.