diff --git a/lib/v2/mdpi/journal.js b/lib/v2/mdpi/journal.js
index 4899fc6f13..0f90f638dc 100644
--- a/lib/v2/mdpi/journal.js
+++ b/lib/v2/mdpi/journal.js
@@ -28,7 +28,11 @@ module.exports = async (ctx) => {
             const title = $2(item).find('.title-link').text();
             const link = `${host}${$2(item).find('.title-link').attr('href')}`;
             const authors = $2(item).find('.authors').find('.inlineblock').text();
-            const doi = $2(item).find('.color-grey-dark').find('a').attr('href').replace('https://doi.org/', '');
+            const doiLink = $2(item).find('.color-grey-dark').find('a').attr('href');
+            let doi = '';
+            if (typeof doiLink !== 'undefined') {
+                doi = doiLink.replace('https://doi.org/', '');
+            }
             $2(item).find('.abstract-full').find('a').remove();
             const abstract = $2(item).find('.abstract-full').text().trim();
             const img = `${host}${$2(item).find('.openpopupgallery').find('img').attr('data-src')}`;