As the irreversible loss in gas-liquid two-phase flow can be described exactly in terms of energy equation, the authors provide anew method in calculating void fraction based on energy model proposed by Lorenzi. An improved energy flow model has now been obtained to treat the experimental data. Three different orifices were used respectively to combine with an oval gear flowmeter in the test. Experimental results indicated that, when the improved energy flow model was used to treat the experimental data, nither the effect of area ratio of oriffice nno the effect of range of quality should be taken into consideration. In the range or this test, (0.00111