Difference between django mongoengine vs mongoengine
Django-mongoengine is a django extension that provides integration with MongoEngine. It is basically like other django-extensions which provides added features.
But MongoEngine is a Document-Object Mapper (think ORM, but for document databases) for working with MongoDB from Python. 
As it uses a simple declarative API, similar to the Django ORM, Django-mongoengine make it work with django. But it is exclusively for working with mongodb using python.

Note

If you use only mongodb then, you can't use admin functionality of Django. You can try using django-non rel. But I will not suggest to go with that. Coz it works with Django-1.3 which is quite old.
If you want to use the admin functionality also and mongodb also then you can use 2 databases first the relational one for admin functionality and then mongodb for other purposes.
What's the difference between django mongoengine and mongoengine
Can i use django default/build-in form mongodb