The overcome the problem of storing and managing big data in today’s web 2.0, new kind of technology is developed which is known as NoSQL. Now-a-days, NoSQL is a very popular as alternative of RDBMS and dealing with large scale data, they also provide high availability and scalability to the distributed systems. In this paper, the authors will discuss on overview of big data challenges, NoSQL database, characteristics and classification of NoSQL database and survey on comparison on popular NoSQL database.