Abstract: Timeresolved measurement system of Xray spectroscopy was constructed by coupling a gated MCP with a flat crystal spectrometer, and the Kshell emission spectra from the corona of laserirradiated aluminum plasma, were measured with a time delay of about 1ns and with an exposure time of about 200ps. Using the approximation of steady collisionalradiative equilibrium model, the interstage line intensity ratios of the Kshell lines of aluminum were given as a function of electron temperature and density. The electron temperatures were deduced from the line intensity ratios. The diagnosed electron temperatures of the plasmas were 1.190(1±27%),1.165(1±27%), and 1.525(1±27%)keV respectively at laser intensity of 2.319×1014, 1.937×1014, and 3.946×1014W/cm2 。