Because broadband tunable external cavity lasers have many advantages,such as frequency stability,low threshold current and tunable wavelength,which are wid ely applied to spectroscopy,biomedicine and optical telecommunication.Due to the dimension of quantum dot lasers is not well distributed with low threshold current and broad gain profile ,the broadband tunable quantum dot lasers are easier to realize.In order to obtain higher performance InAs/GaAs quantum dot external cavity lasers, we have researched a grating external cavity tunable laser based on InAs/GaAs quantum do t (QD) Fabry-Perot (FP) laser diode.We carry on systematical characterizations on In As/GaAs quantum dots external cavity lasers,which mainly include the stability of single-mode lasing,the tuning range of single-mode lasing,the threshold current density,the continuous single-mo de tuning without mode-hoping and the output power measurement.A tuning range of 24.6nm has been achieved at room temperature,cov ering the wavelength from 999.2nm to 1023.8nm,in which hop-free tuni ng has been obtained.The lowest threshold current density is measured as 1525A/cm^2and the output power is above 15mW, with side mode suppression ratio above 35dB.The results of research show that high performance InAs/GaAs quantum dot external cavity lasers have been realized.