diff --git a/src/main/java/com/deare/backend/api/letter/service/LetterServiceImpl.java b/src/main/java/com/deare/backend/api/letter/service/LetterServiceImpl.java
index 999621d..26c78d0 100644
--- a/src/main/java/com/deare/backend/api/letter/service/LetterServiceImpl.java
+++ b/src/main/java/com/deare/backend/api/letter/service/LetterServiceImpl.java
@@ -248,6 +248,10 @@ public void updateLetter(Long userId, Long letterId, LetterUpdateRequestDTO req)
                 String normalizedContent = req.getContent().trim();
                 String newHash = DigestUtils.sha256Hex(normalizedContent);
 
+                if (newHash.equals(letter.getContentHash())) {
+                    return;
+                }
+
                 ReAnalyzeResponseDTO result = letterAnalyzeService.analyzeForUpdate(normalizedContent);
 
                 letterEmotionRepository.deleteByLetter(letter);