Abstract: The modified pRHVnGFP vector containing the green fluorescent protein (GFP) gene was transformed into the lettuce tissue by using the vacuum infiltration method to study the transient transformation system of lettuce. By comparing the conversion efficiency of different Agrobacterium strains EHA105, LBA4404 and GV3103 under the same conditions, and the conversion efficiency of the same Agrobacterium strain under different infection conditions, the infection conditions were finally determined as follows: the lettuce was infected with Agrobacterium LBA4404, the concentration of bacterial suspension OD₆₀₀ was 0.5, acetosyringone was not added, and the pressure state was maintained for 60 s (repeated 3 times) after vacuuming. Under these conditions, the highest conversion efficiency could be achieved.