In cooperation with Alfa Laval Thermal AB Company in Sweden, a steam condensation test rig of a plate heat exchanger (PHE) was set up. The heat transfer and pressure drop characteristics of two kinds of typical operation condition in a PHE were obtained: complete condensation and partial condensation. This article introduces the test rig, various sensors, and the data acquisition system used in the measurements. The process of steam condensation in a PHE is analyzed in detail. The two-phase frictional pressure drop along this wavy channel was obtained from the measured steam condensation pressure drop. The Lockhart-Martinelli model was extended to predict the pressure drop of steam condensation in a PHE and was verified by the experimental results. Based on the data processing of 109 experimental points, a correlation of frictional pressure drop of steam condensation in a PHE is suggested. This correlation is recommended for calculation of the steam condensation pressure drop in a PHE.