diff --git a/7.4/Dockerfile b/7.4/Dockerfile
index a0946e7..2266dcf 100644
--- a/7.4/Dockerfile
+++ b/7.4/Dockerfile
@@ -1,16 +1,17 @@
 FROM stark.doylee.cn/library/php:7-caddy
 
-#  gd pdo_mysql zip
+#  gd pdo_mysql zip gmp
 RUN apk add --no-cache \
     libzip-dev \
     # zip \
     # unzip \
     libpng-dev \
     # zlib1g-dev \
-    # libgmp-dev \
+    gmp-dev \
     && docker-php-ext-configure gd \
     && docker-php-ext-install -j$(nproc) gd \
-    && docker-php-ext-install pdo_mysql \
-    && docker-php-ext-install zip \
+        gmp \
+        pdo_mysql \
+        zip \
     && docker-php-source delete \
     && chown -R www-data:www-data /srv