Freely controlling electromagnetic (EM) waves in desired manners are not only highly important for scientific researches, but also an urgent need in the fields of communications, energy, national defense, etc. To overcome the limitations of natural materials on controlling EM waves, people proposed to construct artificial metamaterials based on subwavelength-sized microstructures with tailored EM properties. Metamaterials have exhibited many fascinating EM effects, such as negative refraction, optical cloaking, and so on. However, after years of development, metamaterials still suffer from many challenges including complexities in structures, high losses, difficulties in optical integrations, etc. Recently, together with other scientists, we proposed the concept of metasurfaces. Utilizing the abrupt phase changes of EM wave scatterings at the meta-atoms and fully exploring the microscopic order of the meta-atoms arrangement, metasurfaces have exhibited much stronger control capabilities on EM wave amplitude, phase, polarization and wavefront distribute, overcoming the bottleneck issues faced by bulk metamaterials. In this article, we will mainly review our key research works on using metasurfaces to control EM waves, including polarization control, wavefront control and dynamic control.