Single microbelt (MB) photodetectors with metal-semiconductor-metal (MSM) structure have been demonstrated and characterized comprehensively. For single-photon absorption, the maximum responsivity of ZnO-MB photodetector can reach as high as 1.4×10⁵ A/W at 20 V bias. The results about photoresponse of MB-detector reveals that two relaxation mechanisms contribute to the carrier decay time. Moreover, the two-photon absorption upconversion photoresponsivity in the single-MB detector has also been realized, which is first report about the two-photon absorption detector to the best of our knowledge. The excellent two-photon absorption photoresponsivity characteristic of MB device can be available not only for detector but also for solar cell and biomedical imaging. Above results present a significant step towards future fabrication of single micro/nano-structure based multiphoton excitation optoelectronic device.