<p>Superconducting hydrides provides a possible route to hunt for high-temperature superconductors. Recent high-throughput calculations suggest hydrides, which are combined by alkali or alkali-earth elements and hydrogen-and-transition-metal units, as potential candidates of superconducting hydrides under ambient pressure. Inspired by the results of high-throughput calculations. Here we propose a strategy to construct high-temperature superconductors by engineering coordination number of known hydrogen-and-transition-metal units in hydrides. Based on hydrogen-and-transition-metal unit [ReH₉]^2- in hydride BaReH₉, we find ternary hydrides BaReH₁₂ with different coordination number of Re from 12 to 14 as pressure increasing. Notably, a icosahedral unit [ReH₁₂]^2-, which exhibits coordination number as high as 12 in hydride BaReH₁₂, drives superconducting critical temperature around 128 K at 100 GPa. Our results suggest that engineering coordination number of hydrogen-metal unit not only trigger the discovery of high-temperature hydride superconductors, but also attracts wide attention from high-pressure physics and coordination chemistry.</p>