The invention relates to an interpolation CIC filter based on a programmable logic device (PLD) and an implementation method thereof, wherein the method comprises the following steps: interpolation of input data signal is completed through an interpolation module; the interpolated data signal is input to a filter group; the filter completes the processing of the interpolated data signal and outputs the processed data signal. Compared with the prior art, the invention maintains identical input/output data bit width of each order due to the optimized design structure of a CIC filter; therefore, cascade connection of each order is completed to avoid the problem of bit width expansion during design and to save register resource occupied during design; meanwhile, the CIC filter is of easier modularization and the expansion of order number can be completed just through simple repeated calling.