In this work, we report a successful facile growth of freestanding lead iodide hydroxide (Pb(OH)I) microwire crystal via hydrothermal method without additives. The properties of samples were investigated by SEM, EDS, and band structure calculation. The results shows that Pb(OH)I microwire crystal is an indirect band gap semiconductor material. Moreover, the Pb(OH)I microwire crystal based photodetector respond to x-ray incident light with a fast, repeatable and stable response. And the sensitivity of Pb(OH)I microwire crystal based photodetector is up to 1.87×10 4 uC Gyair −1 cm −2 . These results substantiate the potential of Pb(OH)I microwire crystal as a candidate material in optoelectronic applications.