The present invention is available for the field of electronic circuit protection, and provides a security cover for enclosing a protective area on the protected PCB and protecting the components in this area. The security cover comprises a flexible PCB that is folded with a receiving space and an opening in a side in the space. The flexible PCB is covered on the protective area of the protected PCB and encloses the components in the protective area. The flexible PCB triggers the related circuits to remove or destroy the information on the components in this protective area in case of physical attack. The present invention is to enclose the key components on PCB via the flexible PCB with the receiving space so as to prevent the key components from being attacked.