Soursop leaf (Annona muricata L) is a plant that has an active component of phenol, namely flavonoids. Flavonoids are known to have antioxidant and antibacterial activity. The aim of this research is to optimize the formula ointment of soursop leaf extract on the bacteria that cause abscess (Staphylococcus aureus) by using the simplex lattice design method. The extraction process was carried out by maseration method with 70% ethanol solvent. The obtained viscous extract is formulated into an ointment preparation with a concentration of 25% to test the physical properties of ointment and antibacterial activity. Test the physical properties carried out from test spread, stickiness, pH and viscosity. The result of physical character test and antibacterial activity have been obtained by using Simplex Lattice Design method and optimum formula result. The optimum formula of the Simplex Lattice Design equation in formula 1 which contains the comparison of vaseline albums: adeps lanae 100%: 0%.