Abstract: As a new somatostatin receptor imaging agent, ^99mTc-depreotide can bind with somatostatin receptors (SSTR) which over express in many sorts of tumor cells. It shows high sensitivity and speciality on evaluating the malignancy and localization of tumors with SSTR overexpression, especially for non-small cell lung cancer (NSCLC). This article gives a review on the bioligy characteristics, radioisotope labeling, biodistribution and tumor imaging of depreotide.