The ISO 304-1985 standard specifies a method for determining the surface tension of surfactants and their solutions by drawing a liquid membrane method. This method is suitable for surfactants in aqueous or organic solutions, including pure liquids or solutions. The standard provides a simple and highly automated Measuring method, which has significant advantages over Miscellaneous surface tension measurement techniques such as capillary tubing or maximum ball pressure method. The implementation of the standard can accurately evaluate the surface properties of liquids, which helps to understand their decontamination, wettability and other characteristics.