This paper discusses the plastic limit load of elbows under combined internal pressure and in-plane closing bending moment. Finite element analysis (FEA) and experiments have been carried out. The results of FEA show that when the ratio of pressure to the limit pressure (P/PL) is smaller than 0.469, the limit moment of elbows increases with the increasing of the pressure; when the ratio (P/PL) is bigger than 0.469, the limit moment of elbow decreases with the increasing of the pressure. The results of FEA are verified by experiments. By fitting the results of FEA, the safety assessment figure for elbow under combined internal pressure and in-plane closing bending moment is drawn. The safety assessment method using the figure is simple and is applicable for the engineering.