Fuciodan is one of the largest polysaccharides in several medical fields, comprising a large number of applications. Gold nanoparticles (Au NPs) play an important role in the field of biomedicine. Fucoidan is considered to be the stabilizing and reducing agent for gold nanoparticles in this investigation. The RSM methodology was used as an optimization for the synthesis of Au NPs. Pure crystalline Au NPs with a medium size of 31 nm (divided between 21 and 44 nm) were formed. In-order aqueous fucoidan extracts have been used to reduce Au NP. In the NPs diffraction pattern, the X-ray diffractometer was used to show clearly that Au NPs are in FCC (Facial Centered Cubic). Fucoidane used to synthesize Au NP displays a surface plasmon resonance (SPR) peak of 555 nm. The presence of sugar molecules on the Fourier infrared spectrometer (FT-IR) has been verified. In addition, the anti-cancer activities of the Au NPs against liver-target cancer cells have been undertaken and desirable results have been obtained. © 2020 Elsevier Ltd