Provided is a clipboard security system and method for improving security of data transmission made through a clipboard which is frequently used in utilization of a computer. An example of the clipboard security system includes a clipboard managing unit for storing data in a clipboard or extracting data from the clipboard in response to a request from one or more objects, in which the clipboard managing unit includes a data encrypting unit for encrypting the data for which storage is requested according to a trust relationship of an object which desires to store the data in the clipboard and a data decrypting unit for decrypting the encrypted data according to a trust relationship of an object which desires to extract the encrypted data stored in the clipboard.