Predicting the structures of crystal is important and relevant to all areas of science in which one would like to know the relative positions of atoms.Because the number of minima in the potential energy surface (PES) of a large system increases exponentially with the number of atoms, thus finding the most stable structure of such system is very difficult.Recently, based on the development of accurate theoretical approaches for calculating energies of assemblies of atoms and computing power, together with the progress in searching methodologies, numerous successful predictions have been obtained.In this talk, I will introduce some of our recent work on crystal structure predictions using a static approach, ab initio random structure searching (AIRSS) and dynamical method called ab initio metadynamics.