A low-dielectric rubber resin material and a low-dielectric metal substrate are provided. The rubber resin material includes a low-dielectric rubber resin composition and inorganic fillers. The low-dielectric rubber resin composition includes: 5 wt % to 40 wt % of a liquid rubber, 20 wt % to 70 wt % of a polyphenylene ether resin, 5 wt % to 30 wt % of a bismaleimide resin, and 20 wt % to 45 wt % of a crosslinker. A molecular weight of the liquid rubber ranges from 800 g/mol to 6000 g/mol. An iodine value of the liquid rubber ranges from 30 g/100 g to 60 g/100 g.