The invention discloses a continuous 
laser device 
spectral line width 
measurement device based on an 
optical frequency comb. The continuous 
laser device 
spectral line width 
measurement device is characterized by comprising an 
optical frequency comb control module, an 
optical frequency comb seed source, an optical 
frequency comb spectrum broadening module, a continuous 
laser generating source, an 
optical beam combining module, an optical frequency selecting filtering module, a beat frequency detecting module and a 
signal reading module. The spectrum of the precisely-controlled optical 
frequency comb is broadened, output light of the precisely-controlled optical 
frequency comb and output light of the continuous laser generating source together enter the 
optical beam combining module, the light spots of two outgoing 
laser beams coincide, and then the two 
laser beams together enter the optical frequency selecting filtering module, two 
laser beams obtained through filtering pass through the beat frequency detecting module, the sizes of light spots are changed through shaping, and the light spots are concentrated on a 
detector, beat frequency signals are obtained through coherent combination, and the output 
spectral width of the continuous lasers to be measured can be contained through the 
signal reading module. The continuous laser device 
spectral line width 
measurement device is stable in structure and high in practicability, the measurement process is rapid and simple, and the output 
spectral width of one or more wave length continuous lasers can be obtained in real time.