User experience characterizes a game. User experience retains users. User experience makes the core of design. This lecture will explain the UED tricks mainly on the mobile platforms (smart phone and tablet) step by step. Through real game cases, inevitable traps in the design process and countermeasures are elaborated. The lecture will expound how to avoid detours and quickly design a high-quality game interface with better user experience from various perspectives based on the characteristics of mobile platforms.