Abstract: A fixing device and a fixing method for a clock tree are provided. The fixing method for the clock tree includes: performing a clock signal path tracking operation on a netlist of a circuit according to timing constraint information to obtain a clock tree circuitry structure; identifying a convergency status of the clock tree circuitry structure to find out at least one clock convergence point, and setting one of a plurality of clock signals on the clock convergence point as a selected clock signal; performing a fix point identification operation on the clock tree circuitry structure based on the selected clock signal to obtain a plurality of candidate fix points; and calculating a plurality weighting values of the candidate fix points, obtaining a plurality of selected fixed points according to the weighting values.