Metal alloys have been widely applied for heterogeneous catalysis, especially alkane dehydrogenation. However, the catalysts always suffer from sintering and coke deposition due to the rigorous reaction conditions. Herein, we described an original approach to prepare a catalyst where highly dispersed Pt clusters alloying with copper were encapsulated in silicalite-1 (S-1) zeolite for propane dehydrogenation (PDH). The introduction of Cu species significantly enhances the catalytic activity and prolongs the lifetime of the catalyst. 0.1Pt0.4CuK@S-1 exhibits a propane conversion of 24.8% with 98.2% selectivity of propene, and the specific activity of propylene formation is up to 32 mol·g_Pt⁻¹·h⁻¹ at 500 °C. No obvious deactivation is observed even after 73 h on stream, affording an extremely low deactivation constant of 0.00032 h⁻¹. The excellent activity and stability are ascribed to the confinement of zeolites and the stabilization of Cu species for Pt clusters.