Journal bearing friction pair system is one of the most general and essential parts used in various mechanical devices. A special test bench is developed for the study on lubrication performance of cylindrical journal bearings. The effect of journal misalignment as a result of shaft bending under load is studied. The results show obvious changes at distribution and value of oil film pressure, oil film thickness and oil temperature of journal bearing due to journal misalignment. The higher the load on the shaft, the larger the journal misalignment resulted from shaft deformation, the more obvious effect on lubrication performance of journal bearing.