Abstract: The influence of Shuanghuanglian Injection on phosphodiesterase 4B gene expression in neutrophils and it’s anti-inflammatory mechanism in neutrophils were studied. The quantity of phosphodiesterase 4B gene expression was detected by semi-quantitative RT-PCR in different time to evaluated the influence of Shuanghuanglian Injection. Expression of phosphodiesterase 4B gene in neatrophils had no notable change after incubating with Shuanghuanglian Injection for 1 h, but significantly reduced (P<0.01) after incubating with Shuanghuanglian Injection for 3 h. The results suggested that Shuanghuanglian Injection can inhibit phosphodiesterase 4B gene expression in neutrophils in certain time, making cAMP content rise and inhibiting activation of inflammatory cells such as neutrophils, consequently, to exert the antiinflammation.