The effect of lanthanum addition on catalytic properties of PtSnK/Al2O3 catalyst for isobutane dehydrogenation was investigated. The catalysts were characterized by nitrogen adsorption, H2 chemisorption, XRF, XRD, XPS, TG, TPO, and NH3-TPD. Results showed that with the appropriate addition of lanthanum, the platinum dispersion increased, and carbon depositions decreased. The presence of La in the PtSnK/Al2O3 catalysts could not only strengthen the Sn−Al2O3 interaction, but also stabilize the oxidation states of Sn species, thus increasing the reaction activity and stability. Among the catalysts investigated, PtSnKLa(0.9 wt %)/Al2O3 had the best catalytic performance. After reaction for 8 h, the isobutane conversion of 49% was achieved with the corresponding isobutene selectivity of higher than 95%.