Annona muricata otherwise known as graviola is a naturally occurring plant found in the tropical regions of Central and South America, Southeast Asia and Africa. The objective of the study is to analyse the phytochemical constituents of the leaf and fruit extract of Annona muricata and to evaluate the antioxidant activity of the extract. Phytochemical screening of the leaf and fruit of A.muricata with various solvents ethanol, xylene, hexane and water was carried out to analyse the maximum yield and the phytoconstituents. Qualitative analysis of phytochemical constituents like tannins, phlobatannins, saponins, flavonoids, steroids, alkaloids, quinines, coumarin, terpenoids and cardiac glycosides were analyzed. Quantitative analysis was done for total phenolics, alkaloids, saponins and flavonoids followed by GC-MS. Antioxidant activity of ethanolic leaf and fruit extract were performed by DPPH and ABTS free radical scavenging activity. The maximum yield was obtained in the ethanolic leaf and fruit extract of A.muricata and the phytochemical screening revealed the presence of tannins, phlobatannins, saponins, flavonoids, steroids, alkaloids, quinines, coumarin, terpenoids and cardiac glycosides in various solvents. Quantitative analysis of ethanolic leaf and fruit extract showed 15.31% and 17.56% per gram of total phenolics, followed by 5.27% and 7.85% per gram of saponins, 3.72% and 3.06% per gram of alkaloids and 2.4% and 3.6% per gram of flavonoids. The GC-MS analysis showed the presence of hexadecanoic acid in the fruit extract at the retention time 22.172 minutes; and octadecanoic acid in the leaf extract at the retention time 19.512 minutes. Antioxidant activity determined by DPPH and ABTS radical scavenging activity of the leaf and fruit extract of A.muricata was compared with standard ascorbic acid and found to have good free radical scavenging activity.