Abstract: This paper introduced a new signal processing method -Compressive Sensing (CS). Recently, an emerging theory of signal acquirement named Compressive Sensing become one of the hottest topics of signal sampling and image processing.It is a novel signal sampling theory under the condition that the signal is sparse or compressible.It has the ability of compressing a signal during the process of sampling.It consists of three main areas:sparse representation matrix, measurement matrix and reconstruction algorithm. This paper mainly introduces the model of Compressive Sensing,and the main reconstruction algorithms,then analyses and compares the algorithms.Finally,the paper lists the main applications of Compressive Sensing.