Abstract: Compared with the traditional single-orifice plate, multi-orifice plates have important application value in wet gas measurement because of its homogenizing the fluid, low noise, low pressure loss and other advantages. In this study, the pressure drop characteristics of two multi-orifice plates, having 48 round holes and 48 slotted holes, respectively, were tested in a horizontal pipe using air and water as the two phases and letting the inflow in the region of flow pattern transition. The results show that there is little difference between the round-hole and slotted-hole multi-orifice plates regarding wet gas pressure drop characteristics. However, it is found that the gas phase multiplier of orifice plates is closely related with variations in the Froude numbers of gas phase and liquid phase. Compared with the experimental pressure drop results, the existing homogenous flow models for orifice pressure drop present an overestimation whereas the existing separated flow models for orifice pressure drop exhibit an underestimation. By correlating the two parameters, i.e. the Froude numbers of gas phase and liquid phase, prediction accuracies of the pressure drop correlation for multi-orifice plates can be improved markedly. Among them, the proposed pressure drop correlation that is derived from a correction of the homogeneous flow model for orifice pressure drop using abovementioned two parameters is optimal in term of prediction accuracies, showing prediction accuracies within ±7% and ±10%, respectively, for the round-hole and slotted-hole multi-orifice plates.