Hi @JL_LZH,
I see what you mean -- because JMP is treating your columns as continuous measurements the binning of observations at increments of 1 results in a pretty strange looking plot. You cannot change the location of the tick marks for a continuous scale, but I think an easy solution will be to change the modeling types of your variables to Ordinal by right-clicking the modeling type and selecting Ordinal, as in the animated gif below.
Does that help get you closer to what you want for this plot?
@julian