Seeing is an important concept in modern astronomy.The flicker and deflection of light caused by atmospheric turbulence during transmission is called seeing.In the ground based large aperture telescope,laser atmospheric transmission and so on,the phenomenon of seeing has an important impact on the image quality of the system.In order to explore the far reaching universe and further carry out related research around the origin of the universe,dark matter and dark energy and other scientific objectives,higher requirements are put forward for the resolution and sensitivity of telescopes.In the aspect of laser transmission,the work of laser communication,satellite remote sensing and optical radar in atmospheric environment is also affected by the seeing.Therefore,how to detect the seeing has become an important topic in the field of astronomical.In this paper,the present situation of various kinds of seeing detection is introduced,and the principles of DIMM,MASS,SCIDAR and CFD are analyzed,and the conclusion and outlook are given at the end.