  Using the form factors calculated in the three-point QCD sum rules approach,
we calculate the new physics contributions to the physical observables of $B_c
\to D_s^* \mu^+\mu^-$ decay in the family non-universal $Z^{\prime}$ model.
Under the consideration of three cases of the new physics parameters, we find
that: (a) the $Z^{\prime}$ boson can provide large contributions to the
differential decay rates; (b) the FBA could be increased by about 47%, 38%, and
110% at most in S1, S2, and ELV, respectively. In addition, the zero crossing
could be shifted in all the cases; (c) when $\hat{s}>0.08$, the value of $P_L$
could be changed from -1 in the SM to -0.5 in S1, and -0.6 in S2, 0 in ELV,
respectively; (d) The new physics corrections to $P_T$ would decrease the SM
prediction about 25% for the cases of S1 and S2, 100% for the case of ELV.
