Owing to the outstanding properties of metallic carbon as well as their great potential applications, design and synthesis of metallic carbon have long attracted considerable attention. In this work, a new three-dimensional metallic carbon (dubbed as Tri-C9) has been built by distorting the sp3 hybridization bond. Our first-principles calculations results indicate that Tri-C9 is a metastable metallic carbon, and that the metallic behavior of Tri-C9 originates from the π bonds near Fermi level. This study offers a new way to design all-sp3 hybridized metallic carbon via distorting the sp3-bond. In addition, a feasible synthesis route for Tri-C9 has been proposed by compressing graphite.