Natural fiber and synthetic fiber are used for many mechanical and structural applications in engineering materials, and technological advancement has made them more valuable. Composite materials that are made from natural fiber reinforcement are widely used in structural components that prevent mechanical and vibrational failures under different loading conditions. This thesis works on the experimental investigation of mechanical properties and free vibration of a false nettle/ glass fiber reinforced polyester polymer composite plate. It was identified due to solve limitation all the mechanical properties, free vibration, and the damping nature of natural and synthetic fiber by false nettle/glass fiber with polyester. In this study , false nettle fibers, glass fiber, and polyester were used to prepare the polymer composites using hand layup assisted compression loading techniques. Alkaline treatment of fiber has been applied to enhance the mechanical property of the composite. The composites material is manufactured with a weight fraction of fiber /polyester 40:60 ratio. FNGPHC materials with an angle of orientation are uni-direction and lamina arrangement [false nettle-glass-false nettle-glass] were manufactured. ACC103 accelerometer with DAQ USB was connected to the computer by integrating the 2017 lab view to measure natural frequency. Both Mechanical properties and natural frequencies of the sample FNGPHC-1(30%FN, 10Gf%, 60%Pl), FNGPHC-2(20%FN, 20%Gf, 60%Pl), and FGPHC-3 (10%FN, 30%Gf, and 60% Pl) materials were compared. it was d iscovered that FNGPHC-2 had the best in tensile, compressive, and impact mechanical properties. Maximum experimental result tensile is 219.78MP, compression strength is 107.33MP, flexural strength is 104MP, impact energy is 46.99J. The maximum natural frequency was recorded in FNGPHC-3 is 85 Hz. Generally, the experimental results have shown that the three sample natural frequencies and damping ratios were decreased with an increased weight ratio of false nettle fiber. These could be better to select for applications that need good mechanical properties and vibration properties to achieve the problem of the research. Increasing the damping of the vibration and the mechanical property of the material is a crucial task in an automotive component design process to prevent failure was attained. Keywords: Hybrid composite, mechanical properties; false nettle; polyester, Experimental Method; Natural frequency