A novel high gain flexible receiving antenna is proposed, which can be used for microwave wireless power transmission(MWPT). The antenna consists of a three-layer toroidal structure in a generalized iterative design with a coplanar waveguide(CPW) feed, and the radiator is integrated on Kapton substrate. In order to improve the gain of the antenna, an air-gap and flexible reflector are loaded at the back of the antenna. The antenna has a peak gain of 9.51dBi at 5.8 GHz. To characterize the stability of the antenna, the fabricated prototype uses three configurations of 85 mm, 60 mm and 45 mm respectively. The S11 of the antenna remains < -10dB, and the maximum harvesting efficiency is 71.3%.