In order to compensate the gain-narrowing and gain-saturation effects and improve the signal-to-noise ratio (SNR) of the output high-power laser pulse, attentions have been paid to the spatial distribution, the temporal profile, and the spectral reshaping in the design of kilo-joule peta-watt chirped pulse amplification (CPA) systems. The multilayer dielectric thin film reflector fabricated by top-down nano-fabrication processes can be used to realize spectral reshaping of high-power chirped pulse. In the design and fabrication of the multilayer dielectric thin film reflector, it is necessary to determine the fabrication control functions appropriately. The control construction function of digital-control fabrication and the etching depth construction functions of the multilayer dielectric thin film reflector for spectral reshaping of chirped pulse laser in Shengguang-Ⅱ system are investigated. The spectral modulation properties of the multilayer dielectric thin film reflector have been analyzed, and the effect of the reflectivity distribution of the multilayer dielectric film reflector approaching to the object function has also been observed.