diff --git a/hutool-core/src/main/java/cn/hutool/v7/core/text/CharUtil.java b/hutool-core/src/main/java/cn/hutool/v7/core/text/CharUtil.java
index 1f80d7a7d8..18589bfd11 100644
--- a/hutool-core/src/main/java/cn/hutool/v7/core/text/CharUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/v7/core/text/CharUtil.java
@@ -419,7 +419,7 @@ public class CharUtil implements CharPool {
 	 * @since 5.6.2
 	 */
 	public static char toCloseByNumber(final int number) {
-		if (number > 20) {
+		if (number < 1 || number > 20) {
 			throw new IllegalArgumentException("Number must be [1-20]");
 		}
 		return (char) ('①' + number - 1);
diff --git a/hutool-core/src/test/java/cn/hutool/v7/core/text/CharUtilTest.java b/hutool-core/src/test/java/cn/hutool/v7/core/text/CharUtilTest.java
index 8ab5fd34d8..23c226a3b2 100644
--- a/hutool-core/src/test/java/cn/hutool/v7/core/text/CharUtilTest.java
+++ b/hutool-core/src/test/java/cn/hutool/v7/core/text/CharUtilTest.java
@@ -19,7 +19,7 @@ package cn.hutool.v7.core.text;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.*;
 
 public class CharUtilTest {
 
@@ -27,7 +27,7 @@ public class CharUtilTest {
 	public void trimTest() {
 		//此字符串中的第一个字符为不可见字符: '\u202a'
 		final String str = "‪C:/Users/maple/Desktop/tone.txt";
-		Assertions.assertEquals('\u202a', str.charAt(0));
+		assertEquals('\u202a', str.charAt(0));
 		Assertions.assertTrue(CharUtil.isBlankChar(str.charAt(0)));
 	}
 
@@ -66,16 +66,16 @@ public class CharUtilTest {
 
 	@Test
 	public void toCloseCharTest(){
-		Assertions.assertEquals('②', CharUtil.toCloseChar('2'));
-		Assertions.assertEquals('Ⓜ', CharUtil.toCloseChar('M'));
-		Assertions.assertEquals('ⓡ', CharUtil.toCloseChar('r'));
+		assertEquals('②', CharUtil.toCloseChar('2'));
+		assertEquals('Ⓜ', CharUtil.toCloseChar('M'));
+		assertEquals('ⓡ', CharUtil.toCloseChar('r'));
 	}
 
 	@Test
 	public void toCloseByNumberTest(){
-		Assertions.assertEquals('②', CharUtil.toCloseByNumber(2));
-		Assertions.assertEquals('⑫', CharUtil.toCloseByNumber(12));
-		Assertions.assertEquals('⑳', CharUtil.toCloseByNumber(20));
+		assertEquals('②', CharUtil.toCloseByNumber(2));
+		assertEquals('⑫', CharUtil.toCloseByNumber(12));
+		assertEquals('⑳', CharUtil.toCloseByNumber(20));
 	}
 
 	@SuppressWarnings("UnnecessaryUnicodeEscape")
@@ -87,4 +87,11 @@ public class CharUtilTest {
 		c = '\u2800';
 		Assertions.assertTrue(CharUtil.isBlankChar(c));
 	}
+
+	@Test
+	public void issueIDFNHETest(){
+		//Console.log(CharUtil.toCloseByNumber(0)); //此时会打印"⑟"
+		assertThrows(IllegalArgumentException.class, () -> CharUtil.toCloseByNumber(0));
+		assertThrows(IllegalArgumentException.class, () -> CharUtil.toCloseByNumber(-1));
+	}
 }