AIM To further study the properties of bile liquid crystals, and probe into the relationship between bile liquid crystals and gallbladder stone formation, and provide evidence for the prevention and treatment of cholecystolithissis.METNODS The optic properties of bile liquid crystals in human body were determined by the method of crystal optics under polarizing microscope with plane polarized light and perpendicular polarized light.RESULTS Under a polarizing microscope with plane polarized light, bile liquid crystals scattered in bile appeared round, oval or irregularly round. The color of bile liquid crystals was a little lighter than that of the bile around. When the stage was turned round, the color of bile liquid crystals or the darkness and lightness of the color did not change obviously. On the border between bile liquid crystals and the bile around, brighter Becke-Line could be observed. When the microscope tube is lifted, Becke. Line moved inward, and when lowered,Becke-Line moved outward. Under a perpendicular polarized light, bile liquid crystals showd some special interference patterns, called Malta cross. When the stage was tuming round at an angle of 360°, the Malta cross showed four times of extinction. In the vibrating direction of 45° angle of relative to upper and lower polarizing plate, gypsum test-board with optical path difference of 530 nm was inserted, the first and the third quadrants of Malta cross appeared to be blue, and the second and the fourth quadrants appeared orange. When mica test-board with optical path difference of 147 nm was inserted, the first and the third quadrants of Malta cross appeared yellow, and the second and the fourth quadrants appeared dark grey.CONCLUSION The bile liquid crystals were distributed in bile in the form of global grains. Their polychroism and absorption were slight,but the edge and Becke-Line were very clear. Its refractive index was larger than that of the bile.These liquid crystals were uniaxial positive crystals. The interference colors were the first order grey-white. The double refractive index of the liquid crystals was Δn = 0.011-0.015.