  The correlation between the charge-order wave vector Q_{CD} and
second-neighbor hopping t' in cuprate superconductors is studied based on the
t-t'-J model. It is shown that the magnitude of the charge-order wave vector
Q_{CD} increases with the increase of t', and then the experimentally observed
differences of the magnitudes of the charge-order wave vector Q_{CD} among the
different families of cuprate superconductors at the same doping concentration
can be attributed to the different values of t'.
