Abstract: The detection of exoplanets becomes a hot research. With some breakthrough in detection and the advance of the space exploring, more than 900 exoplanets have recently been discovered with multiple techniques. Many characteristics quite different with the solar system are found in exoplanets and their orbital configurations. These new phenomena are testing out the traditional planetary formation model. The gravitational instability model and the core accretion model of planetary formation are briefly introduced. At the end of the paper, author introduced a few future exoplanet hunting program of international and China.

Key words: exoplanet system, formation model, hunting program