Background: Persea Americana (family Lauraceae) is universally known as “Avocado” and has precious applications in traditional medicines of South Americans countries and to treat numerous disease. The P. americana (Persea americana) were heretofore reported that used for childhood convulsions, hypoglycemia, epilepsy, dysentery, diarrhea, and also acts as antihypertensive, anti-inflammatory, analgesic, antioxidant, anti-tussive and antimicrobial agents. P. Americana has been numerous compounds like phenolics (polyphenols), tannins, saponins, terpenoids, glycosides and amino acids. Yet, no report exists on the anti-Alzheimer properties of P. Americana. Objective: The objective of the research for evaluation of in vitro and in vivo anti-Alzheimer’s activities of P. Americana leaf extract on scopolamine induced Alzheimer dementia in rats. Methods: Total phenolic content were estimated from P. Americana extract by Folin-Ciocalteu reagent. The neuroprotective effect of P. Americana leaf extract against Scopolamine induced Alzheimer dementia were evaluated. Alzheimer dementia was induced by 1 mg/kg of Scopolamine through intraperitoneally. Ethanolic leaf extract of P. Americana was subjected on rats in low dose (200 mg/ kg, p.o.) as well as high dose (400 mg/kg, p.o.) for investigation of learning and memory. Furthermore, enzymes inhibition activity assay in vitro in order to assess their anticholinesterase properties of P. Americana. Results: P. Americana leaves were found to encompass of Gallic acid equal of total phenolics in extract. P. Americana leaf extract (200 & 400 mg/kg, p.o.) produce expressively enhancement in learning and memory of rats and also significantly decreased acetylcholinestrase level in brain by dose dependent manner when compared with negative control group. Conclusion: The present pharmacological investigation indicated that P. americana leaf extract improve the Alzheimer’s symptoms through the control of acetyl cholinesterase in brain, due to presence of phenolic compounds in P. americana leaf and exhibited adequate anti-Alzheimer’s activity. This concluded that P. Americana leaves has profound of the safe neuroprotective, memory accompaniment mediator and can be used for initial management of Alzheimer’s dementia