Abstract: In order to clarify the relationships between colonization dynamics of endophytic bacteria and the control effects on pepper Phytophthora blight, endophytic bacterial strains were screened by dual culturing against Phytophthora capsici and control effects were measured on the potted seedlings. The endophytic bacteria were identified based on their morphological characteristics, biochemical characteristics and 16S rDNA sequence BLAST. Colonization dynamics of endophytic bacteria in seedlings of Capsicum annuum were also conducted by rifampicin labelling and their relationships with control effects were analyzed. The results showed that three endophytic bacterial strains G9, R15 and J13 had obvious control effects against P. capsici and they were identified as Pseudomonas fluorescens. The strains G9 and R15 could colonize in roots of C. annuum, and J13 could colonize in roots, stems and leaves. Colonization periods of three strains were 30－40 d, and their colonization trended to increase firstly and then decrease. The strains G9 and R15 appeared the highest colonization quantity at 15 d after inoculation. The highest colonization quantity of the strain J13 in roots, stems and leaves presented at 9, 15, 15－20 d after inoculation, respectively, with quantity in root > stem > leaf. The control effect reached 100% and kept for 6 d under the quantity of 9.73×10⁵ cfu·g^-1 in strain G9, and it reached 100% in strain R15 under quantity of more than 6.30×10⁵ cfu·g^-1, which could keep for 14 d. Our research suggested that the 3 endophytic bacteria had great potentials in biocontrol applications on pepper Phytophthora blight.