Serum　levels　of　uric　acid　(UA)　play　an　important　role　in　the　prevention　of　diseases.　Developing　a　rapid　and　accurate　way　to　detect　UA　is　still　a　meaningful　task.　Hence,　positively　charged　manganese　dioxide　nanosheets　(MnO2NSs)　with　an　average　latter　size　of　100　nm　and　an ultra-thin　thickness　of　below　1　nm　have　been　prepared.　They　can　be　well　dispersed　in　water　and　form　stable　yellow-brown　solutions.　The　MnO2NSs　can　be　decomposed　by　UA　via　redox　reaction,　leading　to　a　decline　of　a　characteristic　absorption　peak　(374　nm)　and　a　color　fading　of　MnO2NSs　solution.　On　this　basis,　an　enzyme-free　colorimetric　sensing　system　for　the　detection　of　UA　has　been　developed.　The　sensing　system　shows　many　advantages,　including　a　wide　linear　range　of　0.10–50.0　μmol/L,　a　limit　of　quantitation　(LOQ)　of　0.10　μmol/L,　a　low　limit　of　detection　(LOD)　of　0.047　μmol/L　(3σ/m),　and　rapid　response　without　need　of　strict　time　control.　Moreover,　a　simple　and　convenient　visual　sensor　for　UA　detection　has　also　been　developed　by　adding　an　appropriate　amount　of　phthalocyanine　to　provide　a　blue　background　color,　which　helps　to　increase　visual　discrimination.　Finally,　the　strategy　has　been　successfully　applied　to　detect　UA　in　human　serum　and　urine　samples.　Graphical　Abstract:　[Figure　not　available:　see　fulltext.]　©　2023,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Austria,　part　of　Springer　Nature.