How you can Root For OnePlus One
1) Make sure that your OnePlus One smartphone has at least 50-60% of battery backup in it as the rooting process is a time-consuming one.
2) Now, enable “Unknown Sources” by following this path: Settings -> Security -> Unknown Sources. Only by enabling this option, your device will allow installation of apps from unknown sources.
II. HowTo Root OnePlus One:
1) To get started, download Kingroot app to your OnePlus One device. Once downloaded, tap on kingroot.apk to install the app on your smartphone.
2) After installing kingroot, launch it on your device OnePlus One. Since your device is not rooted, you will get the following message: Root Access Is Unavailable.
4) Once the rooting process is finished, you will get the following message: Root Successfully.