Ti-6Al-4V (Ti64) alloy has limited formability at room temperature. Research conducted to increase the formability of Ti64 alloy reveals that the ductility can be increased by hot forming processes. However, disadvantages of hot forming including high energy consumption and high forming costs are the major obstacles limiting its widespread applications. This study's purpose of increase the limited formability of the Ti64 sheet at room temperature using the pulsating hydraulic bulge test (PHBT) and to investigate the microstructural reasons for the increased formability. In this context, monotonic hydraulic bulge test (MHBT) and PHBT were applied to Ti64 sheets with 0.55 mm thickness at room temperature, and the underlying microstructural reasons for the improved formability were investigated by conducting detailed microstructural characterizations consisting of XRD, SEM, and microhardness testing. Experimental results showed that the dome height of PHBT samples was 15.4% higher than MHBT samples and a more homogeneous thickness distribution was obtained. The thickness and microhardness distributions, dislocation density estimations, and fracture surface analysis were utilized to correlate the increased formability with the microstructure. It was determined that stress relaxation occurred during the PHBT resulting in the achieved improved formability. The decrease in the dislocation density in the early stage of forming prevented the locking of the dislocations and delayed the occurrence of the damage, i.e., leading to the increased bulge dome height. The higher plastic deformation resulting from the increased formability also increased the hardness along the cross-section. The increased formability of the Ti64 sheet during the pulsating bulging and the underlying microstructural reasons discussed in this study are expected to make significant contributions to the current literature for the sheet metals with limited formability at room temperature. That is, without the need for expensive and complex methods such as superplastic forming, hot gas forming or warm hydroforming, the formability of hard-to-form materials can be increased by using pulsating hydroforming method resulting in a more homogeneous thickness distribution.