We　theoretically　propose　a　family　of　structurally　stable　monolayer　halide　perovskite　A(3)B(2)C(9)　(A　=　Rb,　Cs;　B　=　Pd,　Pt;　C　=　Cl,　Br)　with　easy　magnetization　planes.　The　family　materials　are　all　half　metals　with　large　spin　gaps　beyond　1　eV　accompanying　a　single　spin　Dirac　point　located　at　K　point.　When　the　spin-orbit　coupling　is　switched　on,　we　further　show　that　Rb3Pt2Cl9,　Cs3Pd2Cl9,　and　Cs3Pt2Cl9　monolayers　can　open　up　large　band　gaps　from　63　to　103　meV　to　harbor　quantum　anomalous　Hall　effect　with　Chern　numbers　of　C　=　+/-　1　whenever　the　mirror　symmetry　is　broken　by　the　in-plane　magnetization,　and　the　corresponding　Berezinskii-Kosterlitz-Thouless　transition　temperatures　are　over　248　K.　Our　findings　provide　a　potentially　realizable　platform　to　explore　quantum　anomalous　Hall　effect　and　spintronic　applications　at　high　temperatures.