Abstract: By using ultrasonic technology to prepare anhydrous CaSO₄ whisker loaded amides β nucleating agent (βNB) for making polypropylene (PP) composites, the mechanical properties of PP composites were studied, and the influencing factors were explored by DSC and SEM. The results show that using ultrasonic technology to treat CaSO_4W load βNB can greatly improve the impact toughness of the blending of ultrasonic CaSO₄(UCaSO_4W) loaded βBN and PP composites by 56.1%-124.1% compared with pure PP, while untreated CaSO_4W loaded βNB and βNB alone with βNB/PP composites without this effect. DSC and SEM analysis show that the changes of PP beta crystal content in the βNB/PP, CaSO_4W-βNB/PP and UCaSO_4W-βNB/PP composites are related to the addition of βNB content, CaSO_4W and βNB existed antagonism action on PP beta crystal effect; the main cause of the improvement of the impact performance is not the change of PP beta crystal content, but the processing of ultrasonic CaSO_4W and βNB.