In this paper A Square Shape Compact Microstrip Antenna which is suitable for the Mobile Communication i.e. GSM 900 IEEE Band is proposed. To compact the size of Microstrip antenna (MSA), the technique proposed in this paper is meandering the radiating patch and Defected Ground Structure (DGS) technique. In this paper the antenna contains a triangular- slot on the corner of the radiating patch and a square-slot on the ground plane. By using these techniques the size of the proposed antenna is reduced nearly by 90%. The parameters of the designed compact microstrip patch antenna like return loss, VSWR, Gain have been compared with the conventional Microstrip Patch Antenna at the operating frequency of 900 MHz. The performance of the proposed compact antenna is theoretically analysed using CST software and verified experimentally.