Spectrophotometry　was　used　to　determine　the　content　of　oat　β-glucan.　The　effects　of　some　factors　were　investigated,　including　the　concentration　of　Congo　red　and　oat　β-glucan,　reaction　temperature,　pH,　reaction　time,　ion　concentration,　exposure　to　light,　and　the　starch　and　protein　coexisting　in　the　system.　The　binding　equilibrium　constant　K,　the　total　number　of　binding　sites　per　β-glucan　molecule　N,　and　the　binding　number　of　Congo　red　per　β-glucan　molecule　n　were　determined　by　chemometrics　based　on　the　analysis　of　ultraviolet-visible　absorption　spectra.　The　results　showed　that　the　absorbency　had　a　linear　relationship　with　β-glucan　in　the　concentration　from　0　to　10　μg/mL　under　the　condition　that　room　temperature,　Congo　red　concentration　50　μg/mL,　pH　7.5,　reaction　for　30　min,　and　ion　concentration　0.1　mol/L.　Exposure　to　light　had　no　effect　on　the　determination.　Starch　and　protein　had　a　relatively　low　effect　on　the　absorbency.　The　binding　equilibrium　constant　K,　binding　sites　N　and　average　binding　number　n　are　4.08×10　6　,　336　and　297,　respectively　under　the　experimental　conditions.　©　2016,　Dept.　of　JCCOA.　All　right　reserved.