diff --git a/scripts/README.md b/scripts/README.md
index db0a0cd..ef3ec87 100644
--- a/scripts/README.md
+++ b/scripts/README.md
@@ -1,3 +1,4 @@
 # Usage
-[build_exiv2.sh](build_exiv2.sh): Used to build thirdparty library.
-[get_cache_key.py](get_cache_key.py): Used to get cache's key which used in [action/cache](https://github.com/actions/cache).
+`build_*.sh`: Used to build thirdparty library.  
+[get_cache_key.py](get_cache_key.py): Used to get cache's key which used in [action/cache](https://github.com/actions/cache).  
+[gen_mo.py](gen_mo.py): Used to generate .mo file. (i18n)
diff --git a/scripts/gen_mo.py b/scripts/gen_mo.py
new file mode 100644
index 0000000..855a71a
--- /dev/null
+++ b/scripts/gen_mo.py
@@ -0,0 +1,44 @@
+from argparse import ArgumentParser
+from os.path import abspath, dirname, exists,  join
+from os import listdir, makedirs
+from sys import exit as _exit
+from traceback import print_exc
+from subprocess import Popen
+from re import compile
+
+
+def call(*cmd):
+    print(cmd)
+    p = Popen(cmd)
+    p.wait()
+    return p.returncode
+
+
+try:
+    RE = compile(r'^pixiv_downloader\.(.*).po$')
+    p = ArgumentParser()
+    p.add_argument('-p', '--prefix', help='Translation will install at PREFIX/share/locale/<locale>/LC_MESSAGES/pixiv_downloader.mo')  # noqa: E501
+    p.add_argument('-o', '--output', help='Output all translations file in a directory.')  # noqa: E501
+    d = abspath(join(dirname(__file__), "../Language"))
+    arg = p.parse_intermixed_args()
+    if arg.prefix is None and arg.output is None:
+        raise ValueError('--prefix or --output is needed.')
+    for i in listdir(d):
+        if not i.endswith('.po'):
+            continue
+        fn = join(d, i)
+        out = None
+        if arg.output:
+            out = join(arg.output, i.rstrip(".po") + ".mo")
+        elif arg.prefix:
+            out = join(arg.prefix, 'share/locale', RE.search(i).group(1), 'LC_MESSAGES/pixiv_downloader.mo')
+        if out is None:
+            raise ValueError('Failed to get output file name.')
+        out_dir = dirname(out)
+        if not exists(out_dir):
+            makedirs(out_dir, 755, exist_ok=True)
+        if call('msgfmt', fn, '--output', out, '--no-hash') != 0:
+            raise ValueError('Failed to run msgfmt.')
+except Exception:
+    print_exc()
+    _exit(1)