The phase stability in the interface of Sr-doped LaMnO3(LSM)/Gd-doped CeO2(CGO) was examined in this study in order to check the feasibility of using LSM as the cathode material in a low-temperature SOFC(solid oxide fuel cell) using CGO as the electrolyte. For the purpose, CGO powders of Ce0.82Gd0.18O0.91 and two LSM powders having different compositions, La0.9Sr0.1MnO3(LSM10) and La0.5Sr0.5MnO3(LSM50), were synthesized using Pechini method. Then, specimens having the LSM/CGO interface were prepared, heat-treated at 130$0^{circ}C$ for up to 3 days, and analyzed by XRD and STEM/EDX. Face-centered cubic CGO powders of less than 10 nm size were obtained by calcination of polymeric precursor formed in the process at 45$0^{circ}C$. Higher calcination temperature of $700^{circ}C$ was necessary for monoclinic LSM10 and cubic LSM50 powders. LSM powders were coarser than CGO and observed to be in the range of 50~100 nm. No trace of LSM-CGO interaction product was found in the XRD pattern. Also it was known from the concentration profile in the vicinity of the interface that interdiffusion was occurred over only a small penetration depth of ~100 nm order.