Electromagnetic Ion Cyclotron (EMIC) waves in the solar wind have received much attention since they were discovered. EMIC waves are important in the plasma heating and acceleration in the solar wind because they can effectively transfer wave energy to ions via the cyclotron resonance. This paper summarizes the progress of EMIC waves observation and theoretical research in the solar wind, including a series of results obtained from EMIC waves observation in and out of magnetic clouds, Interplanetary Coronal Mass Ejections (ICMEs) sheath region, and the research progress for excitation mechanism of EMIC waves based on observations. Finally, the potential research of EMIC waves in the solar wind in the future is anticipated.