Objective To investigate the effect of intraurethral irrigation with honeysuckle water-decoction on formation of bacterial biofilm on the surface of the catheter. Methods Eighty male patients,who had no history of catheterization and no urinary infection with negative results of urine bacterial culture,were enrolled in the study. All patients were randomly divided into 4 groups with 20 cases in each: group A (patients underwent intraurethral irrigation with honeysuckle water-decoction); group B (intraurethral irrigation with 25% PVP); group C (intraurethral irrigation with normal saline ) and group D (no intraurethral irrigation). The urethral catheters were removed at the 7th day and the bacterial biofilm on the surface of the catheter was examined by scanning electron microscopy (SEM). Results SEM demonstrated uneven- distributed matrixes coated on the surface of the catheter, and bacteria adhered to the matrixes. The average thickness of biofilm in group A, B, C and D was (17.876 ±11.788)μn, (31.090±15. 006)μm,(33.716±11.927)μm, (67.762±23.588)μm, respectively. The average thickness of biofilm in group A, B, C was significantly thinner than that in group D (P<0.01), and the thickness in group A was thinner than that in group B and C (P<0.01), but there was no significance difference between group B and group C (P>0.01). Conclusions Intraurethral irrigation with honeysuckle water-decoction can effectively reduce the formation of bacterial biofilm on the surface of the catheter.