The variations of width and shifts of Ar Ⅰ(2P2→1S5) spectral line emitted from two types of filaments, whose diameters and states are different, in argon/air dielectric barrier discharge with the change in air content were researched for the first time. In order to measure the wavelength shift, Ar Ⅰ(2P2→1S5) spectral line emitted from argon discharge at pressure of 10 Pa was used as a reference line. Regular arrangements of static wide filaments (static big dots) and moving thin filaments (reciprocating moving small dots whose traces are lines) were obtained in discharge at atmospheric pressure when the air content was in the range of 0.4%～4%. The variations of width and shifts of Ar Ⅰ(2P2→1S5) spectral line emitted from the big and small dots with the change in air content were measured respectively. It was found that they all increase with the increasing in air content. The width and shift of small dot are bigger than those of the big dot at any air content. The difference between the former and the latter decreases with the increase in air content firstly and remains basically unchanged after the air content reaches up to 1%.