Abstract: This paper reported that root colonization of rapeseed was measured by Pesudomonas putida P861(Gus) in rhizosphere soil microcosms, and the effects of soil type and soil water content on root colonization of repeseed and movement of P861(Gus) along roots were investigated with technique of gene morking and convention method. In the lime concretion black soil microcosm, the numbers of P861(Gus) in rapeseed rhizosphere under the soil water content of 60% FC and 75% FC were greater than that under 50% FC, P861(Gus) could move to the place of 8cm of root from coated seed, the root colonization density reached 7.5102 and 2.8103cfug-1. The root colonization density of rapeseed reached the maxium (5.5106cfug-1) by P861(Gus), after 3～6days of bacteria coated seeds broadcast, then declined rapidly relative stable lower colonization level (7.6102cfug-1) in grey fluro aquic soil microcosm. The colonization density of P861(Gus) was not gradually decreased from the upper part to the lower part of root.