Bacillus cereus NJSZ-13, an endophytic bacterium with nematicidal activity, was isolated from stems of healthy Pinus elliottii Engelm. Colonization of P. massoniana Lamb. by endophytic B. cereus was studied using scanning electron microscopy and confocal laser scanning microscopy. After the plasmid pGFP78 containing the green fluorescent protein (GFP) gene was transformed into the NJSZ-13 strain, the NJSZ-13:gfp showed the same nematicidal activity and growth curve as the wild-type strain, and the plasmid pGFP78 was stably maintained in strain NJSZ-13 for at least 96 h of bacterial cultivation on medium without antibiotics. After inoculation into Masson pine roots, colonization of the NJSZ-13:gfp strain in plant roots and stems was visualized using confocal laser scanning and the strain was enumerated in inoculated roots and stems. These results suggest that NJSZ-13:gfp is an efficient colonizer of Masson pine and can transfer vertically from roots to stems.