Natural cellulose fiber extract from Pandanus tectorius (Screw pine) leaves is comprehensively investigated as viable alternative for synthetic based fibers made from petro-chemical which is non-degradable and toxic. P. tectorius leaves fiber is extracted and investigated as reinforcement in polymer composite for engineering applications. The habitant are easily found and grown along mangroves and in local jungles located at shallow water. The plant can grow up to 14 m tall. In order to use these continuous cellulose fibers as reinforcement in polymer composites, the microstructural analysis and yield content analysis were carried out using SEM micrographs to establish the certainty of using them as reinforcement fiber. The alkaline, bleaching and combined alkaline-bleach treatments are utilized in extraction of the cellulose fiber to evaluate the effect on the mechanical property. The cellulose percentage of the fiber was increased as the concentration and soaking time were increased. The extraction process resulted in 73 cellulose percentage for 10 wt. NaOH and 120 min treatment. Hence, it caused 87 increment in cellulose percentage compared to the untreated leaf. The combined alkali-bleach cellulose fiber composite showed 40 higher tensile strength compared to untreated cellulose fiber composite at 35 2.8 MPa. © 2019 The Authors.