The increase of integration of distributed generations (DG) requires the network management to be more active. This paper investigates an active voltage control approach by coordinating the reactive power of DG and the operation of onload tap changer (OLTC). A sensitivity model of the V-Q coupling in distribution systems is used in the optimization of the coordinated voltage regulation. The performance of voltage control has been verified and compared with the conventional OLTC control. The results show that this approach is very promising.