diff --git a/AstroLib/Include/AsAttitudeParam_2023.h b/AstroLib/Include/AsAttitudeParam_2023.h
index c714c38fa186509133fb5f51120ee7b55e46966b..e1c7bdaeb18f659131ffc3a644d01dc9ce657f02 100644
--- a/AstroLib/Include/AsAttitudeParam_2023.h
+++ b/AstroLib/Include/AsAttitudeParam_2023.h
@@ -52,6 +52,16 @@ bool	AsQuatToEuler213(const CQuaternion& q, CEuler& euler);
 ///***********************************************************************
 void	AsMtxToEuler321(const CMatrix<double>& mtx, CEuler& euler);
 
+///***********************************************************************
+/// 方向余弦阵转121转序欧拉角
+/// @Author	Ma Zihui
+/// @Input
+/// @Param	mtx		方向余弦阵
+/// @Output
+/// @Param	angle	欧拉角
+///***********************************************************************
+void AsMtxToEuler121(const CMatrix<double> &mtx, CEuler &euler);
+
 ///***********************************************************************
 /// 方向余弦矩阵转为313转序Euler角
 /// @Author	Wang Weili