Deep eutectic solvent (DES), as a promising electrolyte for composite electrodeposition, can effectively reduce the agglomeration of nanoparticles in the electroplating bath and increase the content of nanoparticles in the metal matrix compared with aqueous solution. However, uniform distribution of nanoparticle within metal matrix remains a difficult challenge. In this work, it is demonstrated that a novel in-situ synthesis of SiO₂ nanoparticles in DES can effectively improve the distribution uniformity of SiO₂ nanoparticles in the Ni matrix compared with the conventional addition method, producing a homogenous Ni/SiO₂ nanocomposite coating. The friction and wear tests showed that the uniformly distributed SiO₂ nanoparticles in the Ni matrix significantly improved the tribological properties of the composite coating with stable friction coefficient and wear resistance. The in-situ synthesized method is a promising way to fabricate homogenous nanocomposite coating has better tribological properties than the conventional composite coatings produced by solid particle adding method.