Authors - Ambrish Kumar Sharma, Swati Namdev Abstract - The volume of data is growing gradually in all around by various sec-tors like e-commerce, stock market, medical, banking, education, social networks (Facebook, Twitter, WhatsApp) and also because of the utilization of the internet and mobile apps. Privacy and security have always been important issues with big datasets. Big datasets may be a collection of facts that has huge and multiplex structure like sensors, emails, weblogs and images. Sensitive information about individuals, which is usually evident or hidden in data, is susceptible to various privacy attacks and high risks of privacy disclosure. Constructing a secure and reliable environment for big dataset requires a distinction between existing approaches so that we can develop a unique solution in future for this that maximizes data privacy. This paper offers insights into the overview of big datasets, big dataset privacy problems and various privacy preservation techniques with comparative study used in big datasets.