A kind of double disk gold targets were irradiated by 0.35 μm intense laser at "XINGGUANG Ⅱ" laser facilities and X ray spectra emitted from primary and secondary disk were measured by two soft X ray spectrometers. The properties of X ray spectra modified on secondary disk were investigated. The experimental results were physically analyzed and showed that the X ray spectra emitted from secondary are softened. An X ray streak camera was used to obtain time spatial images emitted from laser plama of double disks targets. The streaking images indicated that collision of plasmas produced by primary and secondary disks occurred because the short distance between double disks.