When a laser beam passes through the static liquid membrane, the light obstructing effect is observed due to surface total reflection. Based on this fact, the similar light obstructing effect was also observed using a white light source, and the obtained obstructed light photos were clear and with no laser speckles. The obstructed light pattern consists of a bright region with significantly high light intensities in the center, two stripshape dark regions outside, and a bright field between these two stripshape dark regions. The boundaries between these bright and dark regions were clear. It was found that the radius of obstructing increases with the increasing of the refractive index. Moreover, the relationship between the liquid membrane refractive index and the radius of light obstructed was derived, and the necessary and sufficient conditions of the obstructed light photos for liquid membrane were also analyzed. Therefore, according to the effect of light obstructing of liquid membrane, a new method for measuring liquid refractive index was proposed. The refractive index of pure water was measured and the obtained results were good in line with those measured by the traditional methods. The proposed method has advantages in simplifying the equipments and operations, and also possesses sound reliabilities and high measuring accuracy.