Compared with traditional medical diagnostic technologies, infrared radiation, X-rays, nuclear magnetic resonance and ultrasound, etc, terahertz technology has become the complementary technology of human imaging or human tissue cancer diagnosis due to its low energy, high spatial resolution and unique analysis ability. Using Terahertz-Time Domain Spectrum(THz-TDS) and terahertz imaging technology, the normal and tumor tissues of the liver and lung are imaged respectively. Based on the relevant experiences from the terahertz spectral detection and imaging measurements of liver, significant results about the terahertz imaging of lung cancer tissue in the range of 1.0 THz-1.75 THz are obtained. The normal and tumor tissues can be clearly distinguished by the point-to-point terahertz pulse imaging; and the higher the selected frequency within the range, the higher imaging resolution can be achieved.