The grating external cavity semiconductor laser has been reported in this paper.It is a perfect source of a real time Raman spectrum analyzer.Using litbrow type external cavity,the first order light diffracted from the grating is send back to provide optical feedback,and the zeroorder diffracted light outputs with stabilized wavelength and narrow band width.The wavelenght is 792.5 nm,the band width is less than 0.08 nm,and the output power is 222 mW.