The present invention relates to a wireless capsule endoscope and a power supply control method thereof. The method includes controlling the power supply of the capsule endoscope wirelessly and automatically adjusting power consumption of the power supply in the capsule endoscope. The wireless capsule endoscope includes a capsule casing, a light generator arranged at outside of the capsule casing, an opto-electronic switching starter arranged in the capsule casing, a power supply, a control module, a posture sensor, an illumination unit, an image processing device and a radio frequency transmission unit. The power supply being driven by the light generator in the present invention can effectively solve the incompatible problem between a traditional magnetic switch and a magnetic control device. Meanwhile, the control module and the posture detector enable the power supply to be in different working status under different states, which can prolong the service life of the power supply of the capsule endoscope.