The construction of neutrino telescopes such as IceCube, ARA, KM3Net, etc. makes important progress toward the neutrino astronomy. With the capability of observing astrophysical high energy neutrinos (AHENs) and of identifying their flavors, neutrino telescopes open a new window on both astrophysics and particle physics. In this report, I will first review briefly different sources of AHENs, in terms of their flavor compositions. The difficulty in resolving the source type is analyzed by combining the accuracies in neutrino telescope observations and the knowledge of neutrino mixing angles. Second, a new parametrization of flavor transition matrix will be introduced, with which I discuss classification of flavor transition mechanisms, including decay models, and probes for transition matrix elements. Finally, neutrino signals in the telescope and discrimination of their flavors will be addressed.