diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/expressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/expressions.scala
index 7666c4a53e5d..d1945478e205 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/expressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/expressions.scala
@@ -523,6 +523,16 @@ object SimplifyConditionals extends Rule[LogicalPlan] with PredicateHelper {
         } else {
           e.copy(branches = branches.take(i).map(branch => (branch._1, elseValue)))
         }
+
+      case e @ EqualTo(c @ CaseWhen(branches, elseValue), right)
+          if c.deterministic &&
+            right.isInstanceOf[Literal] && branches.forall(_._2.isInstanceOf[Literal]) &&
+            elseValue.forall(_.isInstanceOf[Literal]) =>
+        if ((branches.map(_._2) ++ elseValue).forall(!_.equals(right))) {
+          FalseLiteral
+        } else {
+          e
+        }
     }
   }
 }
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SimplifyConditionalSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SimplifyConditionalSuite.scala
index bac962ced461..bdba456c3135 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SimplifyConditionalSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SimplifyConditionalSuite.scala
@@ -199,4 +199,38 @@ class SimplifyConditionalSuite extends PlanTest with ExpressionEvalHelper with P
         If(Factorial(5) > 100L, b, nullLiteral).eval(EmptyRow))
     }
   }
+
+  test("SPARK-33315: simplify CaseWhen with EqualTo") {
+    val a = EqualTo(UnresolvedAttribute("a"), Literal(100))
+    val b = UnresolvedAttribute("b")
+    val c = EqualTo(UnresolvedAttribute("c"), Literal(true))
+    val caseWhen = CaseWhen(Seq((a, Literal(1)), (c, Literal(2))), Some(Literal(3)))
+
+    assertEquivalent(EqualTo(caseWhen, Literal(4)), FalseLiteral)
+    assertEquivalent(EqualTo(caseWhen, Literal(3)), EqualTo(caseWhen, Literal(3)))
+    assertEquivalent(EqualTo(caseWhen, Literal("4")), FalseLiteral)
+    assertEquivalent(EqualTo(caseWhen, Literal("3")), EqualTo(caseWhen, Literal(3)))
+    assertEquivalent(
+      EqualTo(CaseWhen(Seq((a, Literal("1")), (c, Literal("2"))), None), Literal("4")),
+      FalseLiteral)
+
+    assertEquivalent(
+      And(EqualTo(caseWhen, Literal(5)), EqualTo(caseWhen, Literal(6))),
+      FalseLiteral)
+
+    assertEquivalent(
+      EqualTo(CaseWhen(Seq(normalBranch, (a, Literal(1)), (c, Literal(1))), None), Literal(-1)),
+      FalseLiteral)
+
+    // Do not simplify if it contains non foldable expressions.
+    assertEquivalent(EqualTo(caseWhen, NonFoldableLiteral(true)),
+      EqualTo(caseWhen, NonFoldableLiteral(true)))
+    val nonFoldable = CaseWhen(Seq(normalBranch, (a, b)), None)
+    assertEquivalent(EqualTo(nonFoldable, Literal(1)), EqualTo(nonFoldable, Literal(1)))
+
+    // Do not simplify if it contains non-deterministic expressions.
+    val nonDeterministic = CaseWhen(Seq((LessThan(Rand(1), Literal(0.5)), Literal(1))), Some(b))
+    assert(!nonDeterministic.deterministic)
+    assertEquivalent(EqualTo(nonDeterministic, Literal(-1)), EqualTo(nonDeterministic, Literal(-1)))
+  }
 }