The so-called contact Angle (drop Angle) refers to the Angle formed when liquid phase is sandwiched by two tangents of gas-liquid interface and solid-liquid interface at the solid-liquid-gas three-phase junction at which a drop is dropped on a solid horizontal plane. Contact Angle (drop Angle) measuring instrument, mainly used to measure liquid to solid drop Angle, that is, liquid to solid wettability, the instrument can measure the contact Angle of various liquids to various materials. The instrument plays a very important role in the scientific research and production of petroleum, printing and dyeing, medicine, spraying, mineral processing and other industries