Heterogeneous network (HetNet) which can provide the remarkable cell-splitting gain has already received adequate attention in the LTE-A system. Since the standardization of HetNet in HSPA+ is currently in progress, it is necessary to focus on the application of HetNet in the HSPA+ system. Cross- tier interference coordination is one of the crucial issues to be discussed in this area. Considering the HetNet deployment in the multi-flow HSDPA (MF- HSDPA), the main contribution of this paper is to propose a novel cross-tier interference coordination scheme in the MF-HSDPA HetNet. Our method combines the cross-tier multi-flow transmission with the adaptive time domain muting and cross-tier scheduling to deal with the interference problem. System-level simulation results will show the advantages of our proposed scheme.