Objective To study the impact of the morphology of steps on the level meter measurement, and to accurately test the thickness of the films. Methods The problems in the preparation of steps were analyzed, the meddle line strip mask was designed based on these problems, and the new mask was used to prepare steps on different substrates, and then the thickness of the films was measured by level meter. Results The steps near the meddle line of thin films had steep slope, and the upper and lower surfaces were clear. The thickness of the films prepared on the polished Mo substrate had good reproducibility; the films on single crystal silicon substrate had large surface roughness; the upper and lower surfaces of the steps of films prepared on quartz substrates were the smoothest . Conclusion The use of new mask can help to prepare the ideal steps on quartz substrates for relatively accurate test of the film thickness.