The disclosure relates to a road condition determining devicewhich includes: an obtaining module configured to obtain a wheel center vertical acceleration signal of each wheel of a vehicle; a preprocessing module disposed at a post-stage of the obtaining module and configured to preprocess the wheel center vertical acceleration signal to obtain an initial determining signal capable of characterizing a fluctuation of the wheel center vertical acceleration signal; a high-pass filter disposed at a post-stage of the preprocessing module and configured to perform high-pass filtering on the initial determining signal; a low-pass filter disposed at a post-stage of the preprocessing module in parallel with the high-pass filter and configured to perform low-pass filtering on the initial determining signal; and a determining module configured to determine a road condition coefficient based on an initial determining signal obtained after low-pass filtering and an initial determining signal obtained after high-pass filtering.