Abstract　 　　
After more than forty years’ study, it is generally believed that long (> ~ 2 seconds) gamma-ray bursts (GRBs) are produced by collapse of massive stars, while short (< ~ 2 seconds) GRBs are due to merger of two compact binary. However, recent observations indicate that some short GRBs are from collapsars, and some long GRBs are from mergers. The multi-wavelength observations of the emission from GRBs and that from their host galaxies would provide a unique tool to understand the origin of GRBs and the properties of interstellar medium (ISM) surrounding them. These properties are important for unveiling GRB progenitors and the fundamental conditions required within a galaxy to form a GRB. I will analyze the observed data of GRBs to investigate the properties of their progenitors and environment.