Cyber-Physical systems termed as CPS is a system which is an incorporation of both computational algorithms and physical components. Several applications such as smart vehicles, smart cities, smart medicine, and defense systems use CPS as the basis for the development. Artificial Intelligence enables integration of information, analysis of data and uses the resulted insights for securing critical Cyber Physical Systems. In the current scenario, it is considered as a most difficult part to prevent CPS from the adversarial attacks in a world of increasing challengers and hence it is necessary to concentrate on creating resiliency in CPS. This chapter comprises the CPS characteristics, analyzes of CPSs current scenario, security threats faced by CPS, and the solutions for CPS security threats. Also, the discussions about CPS security applications to enhance the security mechanism based on block chain techniques were done. The combination of blockchain and cyber physical system will intercept the existing processes across various fields in the industries. Blockchain mainly enables the CPS to send data or information to private blockchain ledgers for inclusion in shared transactions, which could be used to improve the generalization proficiency-based security applications. This chapter proposed a novel approach for the security enhancement of the SPI incremental model with an efficient secured algorithm. This chapter finishes with a discussion of current research trends and possible future research topics, as well as an overview of recent advancements in the field of AI and blockchain established security for CPS and countermeasures.