diff --git a/lib/notion/getPageProperties.js b/lib/notion/getPageProperties.js
index 27d14047..44f050c5 100644
--- a/lib/notion/getPageProperties.js
+++ b/lib/notion/getPageProperties.js
@@ -243,10 +243,14 @@ function generateCustomizeSlug(postProperties, NOTION_CONFIG) {
     return postProperties.slug
   }
   let fullPrefix = ''
-  const allSlugPatterns =
-    NOTION_CONFIG?.POST_URL_PREFIX ||
-    siteConfig('POST_URL_PREFIX', '', NOTION_CONFIG).split('/')
-
+  let allSlugPatterns = NOTION_CONFIG?.POST_URL_PREFIX
+  if (allSlugPatterns === undefined) {
+    allSlugPatterns = siteConfig('POST_URL_PREFIX', '', NOTION_CONFIG).split(
+      '/'
+    )
+  } else {
+    allSlugPatterns = allSlugPatterns.split('/')
+  }
   const POST_URL_PREFIX_MAPPING_CATEGORY = siteConfig(
     'POST_URL_PREFIX_MAPPING_CATEGORY',
     {},