diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/game/LauncherHelper.java b/HMCL/src/main/java/org/jackhuang/hmcl/game/LauncherHelper.java
index 1ad8fbf86..960a98366 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/game/LauncherHelper.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/game/LauncherHelper.java
@@ -354,7 +354,9 @@ public final class LauncherHelper {
 
                     if (org.jackhuang.hmcl.util.platform.Platform.isCompatibleWithX86Java()) {
                         JavaVersionConstraint.VersionRanges range = JavaVersionConstraint.findSuitableJavaVersionRange(gameVersion, version);
-                        if (range.getMandatory().contains(VersionNumber.asVersion("17.0.1"))) {
+                        if (range.getMandatory().contains(VersionNumber.asVersion("21.0.3"))) {
+                            targetJavaVersion = GameJavaVersion.JAVA_21;
+                        } else if (range.getMandatory().contains(VersionNumber.asVersion("17.0.1"))) {
                             targetJavaVersion = GameJavaVersion.JAVA_17;
                         } else if (range.getMandatory().contains(VersionNumber.asVersion("16.0.1"))) {
                             targetJavaVersion = GameJavaVersion.JAVA_16;
@@ -465,6 +467,11 @@ public final class LauncherHelper {
                                     () -> FXUtils.openLink(OPENJDK_DOWNLOAD_LINK), null);
                             breakAction.run();
                             return Task.fromCompletableFuture(future);
+                        case VANILLA_JAVA_21:
+                            Controllers.confirm(i18n("launch.advice.require_newer_java_version", gameVersion.toString(), 21), i18n("message.warning"),
+                                    () -> FXUtils.openLink(OPENJDK_DOWNLOAD_LINK), null);
+                            breakAction.run();
+                            return Task.fromCompletableFuture(future);
                         case VANILLA_JAVA_8:
                             Controllers.dialog(i18n("launch.advice.java8_1_13"), i18n("message.error"), MessageType.ERROR, breakAction);
                             return Task.fromCompletableFuture(future);
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/JavaVersionConstraint.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/JavaVersionConstraint.java
index 3a43e1c28..9dbbd233c 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/JavaVersionConstraint.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/JavaVersionConstraint.java
@@ -39,6 +39,8 @@ public enum JavaVersionConstraint {
     VANILLA_JAVA_16(JavaVersionConstraint.RULE_MANDATORY, GameVersionNumber.atLeast("1.17"), VersionNumber.atLeast("16")),
     // Minecraft>=1.18 requires Java 17
     VANILLA_JAVA_17(JavaVersionConstraint.RULE_MANDATORY, GameVersionNumber.atLeast("1.18"), VersionNumber.atLeast("17")),
+    // Minecraft>=1.20.5 requires Java 21
+    VANILLA_JAVA_21(JavaVersionConstraint.RULE_MANDATORY, GameVersionNumber.atLeast("1.20.5"), VersionNumber.atLeast("21")),
     // Minecraft<=1.7.2+Forge requires Java<=7, But LegacyModFixer may fix that problem. So only suggest user using Java 7.
     MODDED_JAVA_7(JavaVersionConstraint.RULE_SUGGESTED, GameVersionNumber.atMost("1.7.2"), VersionNumber.atMost("1.7.999")) {
         @Override