diff --git a/AstroLib/Src/AsAttitudeParam_2023.cpp b/AstroLib/Src/AsAttitudeParam_2023.cpp
index a2fbff06af5945887cdee10c49baf97e6d994161..232fb6148ffbc9d727b0269d19f63f3fc7895c4b 100644
--- a/AstroLib/Src/AsAttitudeParam_2023.cpp
+++ b/AstroLib/Src/AsAttitudeParam_2023.cpp
@@ -739,28 +739,24 @@ void AsMtxToEuler132(const CMatrix<double>& mtx, CEuler& euler)
 ///***********************************************************************
 void AsMtxToEuler212(const CMatrix<double>& mtx, CEuler& euler)
 {	
-	double epsilon = 1e-8;
-	double theta = 0, psi = 0, phi = 0;
-	theta = acos(mtx[1][1]);
-	if (fabs(sin(theta)) < epsilon)
+	double epsilon = 1e-12;
+	if (mtx[1][1]<(1 + epsilon) & mtx[1][1]>(-1 - epsilon))
 	{
-		if (fabs(theta) < epsilon)
-		{
-			phi = 0;
-			psi = atan2(mtx[0][2], mtx[0][0]);
-		}
-		else //theta == pi
-		{
-			psi = 0;
-			phi = atan2(-mtx[0][2], mtx[0][0]);
-		}
+		euler.m_Angle2 = acos(mtx[1][1]);
+	}
+	else
+	{
+		cout << "error，输入方向余弦矩阵存在大于1或小于-1的元素";
+	}
+
+	if (fabs(sin(euler.m_Angle2)) < epsilon)
+	{
+		euler.m_Angle1 = 0;
+		euler.m_Angle3 = atan2(mtx[0][2], mtx[0][0]);
 	}
 	else //sin(theta) != 0
 	{
-		psi = atan2(mtx[1][0], -mtx[1][2]);
-		phi = atan2(mtx[0][1], mtx[2][1]);
+		euler.m_Angle1 = AsCPI-atan2(mtx[1][0], -mtx[1][2]);
+		euler.m_Angle3 = AsCPI-atan2(mtx[0][1], mtx[2][1]);
 	}
-	euler.m_Angle1 = phi;
-	euler.m_Angle2 = theta;
-	euler.m_Angle3 = psi;
 }
\ No newline at end of file