Lead　halide　perovskites　have　shown　high　performance　in　radiation　detection　techniques　owing　to　their　excellent　optoelectronic　properties　and　stability.　However,　the　high　resistivity　of　the　CsPbBr3　radiation　detector　is　intensively　dependent　on　the　growth　quality　of　the　single　crystal,　which　is　closely　related　to　temperature　gradients　or　the　introduction　of　additives.　Herein,　a　CsPbBr3　single　crystal　with　high　radiation　performance　is　grown　based　on　the　proposed　temperature-concentration　balance　(TCB)　method.　The　prepared　perfect　single　crystal　remains　high　quality　in　repeated　experiments,　which　belongs　to　the　Pnma　space　group,　benefiting　from　the　effective　growth　method.　Based　on　the　CsPbBr3　single　crystal,　the　fabricated　detector　with　the　asymmetrical　Au-In　electrodes　demonstrates　outstanding　linearity　under　reverse　bias.　It　exhibits　a　lower　dark　current　(2.66 × 10−2　nA)　and　high　resistivity,　which　helps　acquire　a　broader　radiation　measurement　range.　Moreover,　the　emission　spectrum　of　the　CsPbBr3　single　crystals　exhibits　a　sharp　emission　peak　at　527 nm　and　narrower　full　width　at　half　maximum,　making　crystals　easily　couple　into　radiation　detectors.　These　findings　provide　insight　into　the　growth　and　regulation　of　CsPbBr3　crystal　for　more　extensive　applications　in　radiation　detection　in　the　future.　©　2025　The　Author(s).　Advanced　Electronic　Materials　published　by　Wiley-VCH　GmbH.