Time-integrated X-ray spectra produced by aluminum wire-array Z-pinch plasmas are measured with a novel mica uniform dispersion crystal spectrograph at Yang accelerator. By using the collisional-radiative equilibrium (CRE) model, the average electron temperature is estimated to be 500 eV from the intensity ratios of Ly-α/He-α line and Ly-β/He-ε line. The plasma core electron temperature is around 1215 eV derived from the continuum slope with linear fitting. The experimental result demonstrates that the electron temperature shows a nearly linear decrease from the axis to the outer edge of the pinch in this implosion. It is shown that the intensity ratio is an efficient tool for inferring electron temperature and the continuum slope provides essential information of core electron temperature of aluminum wire-array implosion.