Abstract: The effects of potassium alkyl-phosphate(PK) on the antistatic and friction properties of polyester(PET) staple fiber were discussed from both macroscopic and microscopic aspects.The results demonstrated that the mono/diesters ratio,temperature and humidity had considerable influence on the antistatic property of fiber.The particle size of PK emulsion had little influence on the antistatic property but marked influence on the friction.In addition,the morphology of surface of fiber was observed by environmental scanning electronic microscopy(ESEM).It indicated that the surface of fiber can be covered well by PK when the absorption amount is 0.1 percent,whereas C_(18)PK results in more deposits on the surface of fiber than C_(12)PK when the absorption amount is 0.3 percent.