Medicinal herbs or plants have been known to be an important potential source of therapeutics or curative aids. The use of medicinal plants has attained a commanding role in health system all over the world. Many countries in the world, that is, two-third of the world’s population depends on herbal medicine for primary health care. One such plant is Lagerstroemia speciosa (L.) Pers. (Synonyms: Adambea glabra Lam., Lagerstroemia major Retz., Munchausia speciosa) is locally known as Jarul or Banaba (Family: Lythraceae). It is a small to medium sized or rarely large deciduous or semi-deciduous tree that grows abundantly in tropical and subtropical regions Leaves of the species have been traditionally used over thousands of years as folkloric treatment by the native Indians and Japanese for illness, ailments particularly for lowering blood sugar levels and weight loss. The flower extracts of the species has some pharmacological properties like antioxidant and antimicrobial activities, whereas fruit extracts reported anti-nociceptive, anti-diarrhea and cytotoxic activities. Research on leaf extracts reveals that anti-bacterial, anti-viral, anti-inflammatory, anti-obesity, antifibrotic, anti-diabetic and xanthine oxidase inhibition, diuretic, decongestant activities and roots are applied for treating mouth ulcers. In addition to that bark is used to relieve the abdominal pains. The aim of this work is to study Qualitative and quantitative parameters of Phytochemicals from plant extract of lagerstroemia speciosa. The leaves of plant were collected and subjected to extraction. Further phytochemical test and quantitative estimation of phenol& flavonoid was performed. The results showed that the yields were found to be (13.51 % w/w of crude drug) of Methanolic extract with orange black colour semisolid mass for Lagerstroemia speciosa Leaves. The phytochemical test revealed the presence of Alkaloids, Carbohydrates, Flavonoids, Proteins & Amino acids, Phenols, Diterpenes. Saponins. Total phenolic content in methanolic extract of Lagerstroemia speciosa Leaves was observed to be 18.24± 0.154 mcg/ml while the total flavonoid content was noticed to be 28.45 ± 0.121 mcg/ml. From these outcomes it can be understood that the leaves of Lagerstroemia speciosa posses appreciable amount of phenol & flavonoids. Keywords: Lagerstroemia speciosa, Phytochemicals, Flavonoids, Phenol