Highlights from gamma-ray observation by the Tibet ASgamma experiment.

The Tibet ASgamma experiment is located at 4,300m above sea level, in Tibet, China.The experiment is composed of a 65,700 m2 surface air shower array and 3,400 m2 underground water Cherenkov muon detectors. The surface air shower array is used for reconstructing the primary particle energy and direction, while the underground muon detectors are used for discriminating gamma-ray induced muon-poor air showers from cosmic-ray (proton, helium,...) induced muon-rich air showers.Recently,the Tibet ASgamma experiment successfully observed gamma rays in the 100 TeV region from some point/extended sources as well as sub-PeV diffuse gamma rays along the Galactic disk.In this talk, The observational results as well as their interpretations will be presented, followed by some future prospect.