This paper presents a method to design a high efficiency energy receiving coil for Micro-Ball endoscopy. The remained space for energy source is extremely small (below 6.6∗6.6∗6.6mm3) in Micro-Ball. Ferrite core is adopted to improve the coupling coefficient. Based on detailed analysis of power loss in the receiving coil, parameters such as number of turns, frequency, types of wires (solid wire or litz wire) was optimized to improve the quality factor of the receiving coil. Ultimately, the coupling coefficient has an improvement of 80%. Experiments shows that the quality factor of the receiving coil (a=b=6.6mm, h=6.6mm) can reach 47 with solid wire and 96 with litz wire at 1.5MHz. Hybrid resonant is proposed to fit in with the load of the Micro-Ball. The AC-AC transmission efficiency of the receiving coil with litz wire is 6.3% in the worst case.