Abstract: CaCu₃Ti₄O₁₂ and La2/3Cu3Ti4O12 materials were prepared by solid reaction process, and the conductance properties were measured and studied. The experimental data show that the conductancetemperature curves of CaCu₃Ti₄O₁₂ and La_2/3Cu₃Ti₄O₁₂ are similar. In the lower temperature range (<150 K), the conductance increases with the temperature and the samples exhibit negative resistancetemperature properties. In the temperature range of 150－170 K, the conductance reaches its maximum. Then, in the higher temperature range (170－250 K), the conductance decreases with the temperature. But the maximum value of conductance of CaCu₃Ti₄O₁₂ is about 3 times larger than that of La_2/3Cu₃Ti₄O₁₂. Further analysis shows that after Ca ^_2＋ is replaced by La ^_3＋, onethird of vacancies remain in A sites, which results in the activation energy of La_2/3Cu₃Ti₄O₁₂ reaching 1.01 eV. The higher activation energy is the main cause of lower conductance of La_2/3Cu₃Ti₄O₁₂.