The $BaHfO_3$ (BHO) buffer layer on the IBAD MgO template was turned to be effective for a successful fabrication of $GdBa_2Cu_3O_{7-{delta}}$ (GdBCO) films with high critical current density ($J_c$). Both the BHO buffer layers and GdBCO films were prepared by pulsed laser deposition (PLD). The effects of the PLD conditions, including substrate temperature ($T_s$), oxygen partial pressure ($PO_2$), and deposition time on the in-plane texture, surface roughness, and microstructures of the BHO buffer layers on the IBAD MgO template were systematically studied for processing optimization. The c-axis oriented growth of BHO layers was insensitive to the deposition temperature and the film thickness, while the in-plane texture and surface roughness of those were improved with increasing $T_s$ from 700 to $800^{circ}C$. On the optimally processed BHO buffer layer, the highest $J_c$ value (77 K, self-field) of 3.68 $MA/cm^2$ could be obtained from GdBCO film deposited at $780^{circ}C$, representing that BHO is a strong candidate for the buffer layer on the IBAD MgO template.