Several　methods　of　analysis　used　for　the　design　of　base-isolated　buildings　are　proposed　in　many　structural　specifications.　According　to　different　structural　codes,　limited　conditions　of　equivalent　linearization　of　the　friction　pendulum　system　(FPS)　and　application　scopes　of　simplified　linear　static　analysis　(LSA)　are　introduced.　LSA　of　a　reinforced　concrete　frame　building　isolated　by　FPS　is　performed　and　compared　with　fast　nonlinear　time-history　analysis　(FNA)　to　evaluate　the　suitability　of　the　simplified　method.　Based　on　a　specific　spectrum　used　in　the　new　Italian　code,　seven　spectrum-compatible　earthquake　ground　motions　are　selected　and　scaled　as　seismic　input.　To　perform　both　linear　and　nonlinear　analyses　systematically,　a　program　is　specially　developed　by　MATLAB　in　combination　with　a　commercial　software.　Base　displacement,　story　shear　force,　and　energy　dissipation　are　selected　as　response　indicators.　The　results　reveal　that,　as　a　substitute　for　the　exact　nonlinear　analysis　method　in　the　preliminary　design　of　base-isolated　buildings,　the　LSA　method　yields　conservative　estimates　in　base　displacement　and　total　input　energy.　However,　because　of　the　uniform　acceleration　profile　assumed　over　the　structural　height,　the　story　shear　forces　are　significantly　underestimated　by　LSA.