Circularly polarized light (CPL) has been given great attention because of its extensive application. While several devices for CPL detection have been studied, their performance is affected by the magnitude of photocurrent. In this paper, a self-powered photodetector based on hot electrons in chiral metamaterials is proposed and optimized. CPL can be distinguished by the direction of photocurrent without external bias owing to the interdigital electrodes with asymmetric chiral metamaterials. Distinguished by the direction of photocurrent, the device can easily detect the rotation direction of the CPL electric field, even if it only has a very weak responsivity. The responsivity of the proposed detector is near 1.9 mA/W at the wavelength of 1322 nm, which is enough to distinguish CPL. The detector we proposed has the potential for application in optical communication.