以Ａｌ＿２Ｏ＿３和Ｌａ＿２Ｏ＿３为原料，采用烧结法制备了Ｌａ－β－Ａｌ＿２Ｏ＿３固体电解质。在１０￣（－３）～１０￣６Ｈｚ频率范围内，于８００～１５００℃温度区间测定了电解质的阻抗谱，并计算得到电导率。用该固体电解质组装成只有镧的化学位差的电池，得到了稳定的电池电动势，计算了待测合金中镧的活度，由此说明该固体电解质呈现Ｌａ￣（３＋）离子导电性，有希望制成Ｌａ传感器，测定钢和铸铁液中溶解态镧的活度。也可用于高温固态合金钢活度测定。 The La-β-Al 2 O 3 solid electrolyte was prepared by sintering method using Al 2 O 3 and La 2 O 3 as raw materials. In 10 ~ (-3) ~ 10 ~ 6Hz frequency range, measured at 800 ~ 1500 ℃ temperature range of the electrolyte impedance spectra, and calculate the conductivity. The solid electrolyte was assembled into a lanthanum-only cell with a chemical difference, a stable cell electromotive force was obtained, and the activity of lanthanum in the alloy under test was calculated. Thus, the solid electrolyte exhibited La 3+ ion conductivity, It is hoped to make a La sensor to determine the activity of dissolved lanthanum in steel and cast iron solutions. Can also be used for high temperature solid-state alloy steel activity measurement.