Two-dimensional topological materials are ideal candidates for low-dissipation electronic devices due to their non-dissipative edge states. Graphene, as a typical two-dimensional system, can theoretically exhibit the quantum spin Hall effect under the spin-orbit coupling interaction. However, the band gap in graphene is only on the order of micro-electron volts, which seriously restricts its practical applications. In this work, using the first-principles calculations, we investigate the electronic structures and topological properties of strained Zr₂C₁₂, which is formed by substituting doping graphene with the group ⅣB 4d transition metal Zr. The phonon spectrum calculation confirms that the freestanding Zr₂C₁₂ exhibits excellent dynamic stability. When the spin-orbit coupling is excluded, the bands cross linearly at the K point near the Fermi level, indicating the Dirac semimetal phase of freestanding Zr₂C₁₂. The Fermi velocity of the Dirac point is 0.677×10⁶ m/s, which is approximately two-thirds of that in graphene (~1.00×10⁶ m/s). When the spin-orbit coupling is considered, the Dirac point opens a gap of 4.09 meV, which is three orders of magnitude higher than that in undoped graphene. The parity analysis reveals that the Z₂ topological invariant of the freestanding Zr₂C₁₂ is 1, indicating that the system transitions into a two-dimensional topological insulator. We also study the properties of Zr₂C₁₂ under strain regulation. The calculation results show that the system remains dynamically stable over a wide strain range from –5% to 6%. When the spin-orbit coupling does not exist, the conduction band energy at the Γ point continuously rises with the increase of strain, and the system maintains the Dirac semimetal phase. After considering the spin-orbit coupling, the system remains in the nontrivial topological insulator phase over a wide strain range from –5% to 6%, demonstrating robust topological properties. The band gap at the Dirac point first decreases and then increases as strain increases. When applying –1.6% compression strain, this band gap decreases to a minimum value of 0.059 meV. When the strain further increases to 6%, this gap increases to a maximum value of 8.41 meV. The calculations of edge states of Zr₂C₁₂ under a 6% expansion strain show that the gapless edge states connect the conduction bands and the valence bands, which further verifies the non-trivial topological properties of this system under strain regulation. This study expands the research on transition-metal-doped graphene systems, providing a good material platform for further studying low-dissipation electronic devices and quantum computing and communication.