This paper investigates the optimization of wireless power transmission and its application to Micro-Ball Endoscopy. Wireless power transfer via novel Asymmetric Resonant Coupling structure is proposed to deliver power to Endoscopic Micro-Ball to read images after it’s excreted from human body. The most important advantage of this structure is its applicability to medical applications with very limited volume on secondary side and requirement for very high power deliver efficiency. To evaluate this structure precisely, a circuit model considering skin, proximity, eddy, and radiation effects is analyzed in detail. Theoretical calculation and progress of optimization is given. Prototype of Micro-Ball including primary, middle resonant and cub-like full-direction secondary receive coils indicates 200mW can be successfully delivered, which can meet the requirement of the Micro-Ball endoscopy application. For the worst-case orientation between primary and secondary side, the efficiency reaches 41%, and for the best-case orientation, the efficiency is 53%. Comparing to conventional structure, Asymmetric Resonant Coupling Structure improves power efficiency by 13%.