Pulsars are supposed to be powerful probes for the internal dynamics of the Galactic globular clusters (GCs). During the motion in the clusters, the pul-sars experience a drag force through dynamical friction (DF). We show that the effects of DF on the acceleration as well as the related timing parameters are significant for millisecond pulsars in the inner regions of core-collapsed clusters with high core densities. We also consider the influence of the IMBH that may exist in the center of a GC on the drag force, and found that it can improve dramatically the acceleration within its influenced region. The timing effects of the drag force may be used to increasing the accuracy of timing parameters, and may provide a unique tool to study the role of DF in GC dynamics.