diff --git a/seahub/templates/snippets/file_content_js.html b/seahub/templates/snippets/file_content_js.html
index 1cc9eccdba..6ef653ebc3 100644
--- a/seahub/templates/snippets/file_content_js.html
+++ b/seahub/templates/snippets/file_content_js.html
@@ -96,6 +96,10 @@ try {
     PDFJS.workerSrc = '{{MEDIA_URL}}js/pdf.worker.js';
     $('#file-view').html('<div id="pdf"><span class="loading-icon loading-tip"></span></div>');
     PDFJS.getDocument("{{ raw_path|escapejs }}").then(function(pdf) {
+        if (pdf.numPages > 50) {
+            feedback("{% trans "This file has more than 50 pages, and only the first 50 will be shown here." %}", 'info');
+        }
+
         var $loadingTip = $('#pdf .loading-tip');
 
         // show at most 50 pages
diff --git a/seahub/templates/snippets/office_convert_js.html b/seahub/templates/snippets/office_convert_js.html
index 79af596c15..c0bae88725 100644
--- a/seahub/templates/snippets/office_convert_js.html
+++ b/seahub/templates/snippets/office_convert_js.html
@@ -63,6 +63,10 @@ OfficePreviewer.prototype.check_page_status = function() {
         cache: false,
         dataType: 'json',
         success: function(data) {
+            if (data.info.pages > data.info.final_pages) { // total pages > shown pages
+                feedback("{% trans "This file has more than 50 pages, and only the first 50 will be shown here." %}", 'info');
+            }
+
             var status = data['status'];
             switch (status) {
             case 'PROCESSING':
diff --git a/seahub/templates/view_file_pdf.html b/seahub/templates/view_file_pdf.html
index 458efc9d5b..7f291dcb6d 100644
--- a/seahub/templates/view_file_pdf.html
+++ b/seahub/templates/view_file_pdf.html
@@ -30,6 +30,10 @@ try {
     PDFJS.workerSrc = '{{MEDIA_URL}}js/pdf.worker.js';
     $('#file-view').html('<div id="pdf"><span class="loading-icon loading-tip"></span></div>');
     PDFJS.getDocument("{{ raw_path|escapejs }}").then(function(pdf) {
+        if (pdf.numPages > 50) {
+            feedback("{% trans "This file has more than 50 pages, and only the first 50 will be shown here." %}", 'info');
+        }
+
         var $loadingTip = $('#pdf .loading-tip');
 
         // show at most 50 pages