Bubbly flow occurs in the subcooled boiling section of the fuel assembly in pressurized water reactor (PWR) cores. Two-fluid model is considered one of the most accurate methods for describing two-phase flow because it establishes the separate flow conservation equations of gas and liquid flow and considers the interfacial interactions. Numerous constitutive equations have been established to achieve the closure of the two-fluid model. Great efforts have been made to establish an experimental database for interfacial parameters. Liquid phase turbulence is critical in determining interfacial parameters such as void fraction, interfacial area concentration, and bubble velocity that affect heat and mass transfer between phases. However, the measurement of the liquid flow field in two-phase flow has been a difficult problem that needs to be overcome for a long time. Limited experimental data restricts the modeling of turbulence models. Therefore, establishing a high-quality experimental database containing gas and liquid phase parameters plays a vital role in the closure of the two-fluid model and the validation of nuclear system analysis codes. A 5 × 5 rod bundle channel air–water two-phase flow experimental facility is established in this paper to further investigate the liquid-phase turbulence characteristics. The particle image velocimetry technology (PIV) is used to measure the turbulence information, including the axial and lateral velocity, fluctuation velocity, turbulence intensity, Reynolds stress, and turbulent kinetic energy for the liquid phase. The PIV measurement of two-phase flow is different from that of single liquid-phase flow because the obstruction and reflection of interfaces can seriously affect the accuracy of the measurement. The planar laser-induced fluorescence (PLIF) technique using fluorescent particles and high-pass filters is used to reduce the influence of bubbles. In addition, post-processing of the original data images can further filter out the stray light introduced by bubbles. A four-sensor conductivity probe is used to measure the local interfacial parameters such as void fraction, interfacial area concentration, bubble velocity, and Sauter mean diameter to compare the influence of local bubble distribution on turbulence. Based on the obtained experimental database, the distribution characteristics of the liquid phase flow field in the rod bundle channel and its influence mechanism on bubble interaction were studied. Moreover, the influence of the spacer grid on two-phase flow has also been further analyzed.