Based on a room-temperature-operated THz fiber-scanning near-field imaging system,we demonstrate the capability of THz imaging for diagnosing human liver cancer.By THz near-field mapping of the absorption constants of liver tissues,the acquired images can clearly distinguish cancer from normal tissues fast,automatically,and correctly without pathological H&E staining examination.Accordingly,the studied THz imaging system has valuable potential applications in clinical cancer diagnosis.With the help of THz imaging,we can expect to economize the use of hospital and human resources.