Spirulina plank tonic blue green algae are gaining increasing attention because of its nutritional and medicinal properties. The attempt of this work was to compare the antibacterial activity of Spirulina sp. isolated from Lonar Lake commercially available in Market. Organic solvents and aqueous extracts of Spirulina were prepared and Phytochemical were identified and the extracts were evaluated for their antibacterial activities against Escherichia coli, Staphylococcus aureus, Salmonella typhi, Proteus vulgaris, Klebsiella pneumoniae, and Pseudomonas aeruginosa by disc diffusion method. Methanol, ethanol, acetone and aqueous extracts of Spirulina platensis showed good antibacterial activity against Staphylococcus aureus, Salmonella typhi and Escherichia coli by both diffusion methods. Preliminary Phytochemical analysis reveals that the presence of alkaloids, carbohydrates, glycosides, sterols, terpenoids, proteins, tannins, saponins, and flavonoids whereas proteins and tannins were not present in methanol extract. Ethanol extract showed the presence of terpenoids and flavonoids while including these glycosides are absent in acetone extract. Saponins present in all the extracts.