The dimension of quantum dot lasers (QDL) is not well distributed with low thres hold current and broad gain profile,so the broadband tunable QDL is easier to realize .In this paper,we demonstrate a grating external cavity (EC) InAs/InP(100) QDL based on InAs/InP quantum dot Fabry-Perot laser diode.In addition,we characterize this EC InAs/InP QDL,including the stabi lity of single mode lasing, the tuning range of single-mode lasing,the threshold current density,the continuous mode-hop-free tuning range and the output power.This EC InAs/InP QDL follows Littrow configuration,operating in continuous-wave (CW) mode at 1.6μm with a fixed output beam.The EC-QDL ex hibits coarse single mode tuning range of 56.6nm and a continuous mode-hope free fine tuning range of 30GHz.Optical output power of 8mW can be obtained near the center wavelength of 1.6μm and more than 30dB side mode suppression ratio in the mode-hop free fine tuning range is also realized.