The objective of this work was to investigate the effect of surface improvement on human hair fiber (HF) based high-density polyethylene (HDPE) reinforced polymer composites. A universal testing machine was used for the characterization of the mechanical behaviors of different types of HF base reinforced HDPE composites, and studies were conducted for the optimization of male/female fiber percentage (15% HF) in polymer composites. The alkali treatment (AT) and acrylic acid treatment (AAT) of HF reinforced HDPE composites showed a remarkable improvement in tensile strength (upto 15.487MPa and 15.638MPa, respectively), which was significantly changed in comparison to the tensile strength of untreated composites. FTIR and SEM test were used to characterize the fiber surface and HF/HDPE reinforced composites. Water absorption kinetics was investigated for the study of diffusion mechanism and kinetics of composites materials, which would be useful to boost the applications of the composite in different areas.