In order to explore the influence of different outlet pressure difference and feeding speed on the expansion effect of carbon fiber bundles in the air spreading process， an air spreading platform was established according to Venturi principle. The process of carbon fiber broadening was recorded， and the ratio and uniformity of carbon fiber broadening at different stages were calculated under different technological parameters. The results show that the carbon fiber bundles with a broadening rate of more than 400% and a broadening uniformity of more than 90% can be obtained by the air flow spreading test platform.The expansion rate of the carbon fiber bundle is positively correlated with the outlet pressure difference and negatively correlated with the feeding speed. The evenness of the expansion of the carbon fiber bundle is negatively correlated with the outlet pressure difference and positively correlated with the wire feeding speed.