Purpose: In the past, big data was the concern of governments and large commercial industries, and so these organizations had infrastructures separate from the public network to store and process their data. But today, big data is easily accessible to everyone through cloud infrastructure. In recent years, with the explosive development of the Internet, data storage and data processing technologies, privacy has been one of the major concerns in data mining Methodology: In this paper, after examining the dimensions and key components of flax data, privacy in big data; BlockChain solution for privacy protection is examined. Findings: This topic provides new opportunities for researchers in knowledge processing tasks. However, these opportunities often bring challenges as well. Originality/Value: Big Data means a very large database that can be structured or unstructured. Big data is a database that is constantly getting bigger with the increase of information. Also with the rapid advancement of the Internet, data storage and data processing technologies, big data privacy has attracted a lot of attention. Before applying big data technology to mass applications and applications, a basic issue called privacy must be explored.