Abstract: Agrobacterium mediated transformation using EHA105, PG gene was transferred into processing tomato B04 plants. Through the influence of explants conversion factor (pre- cultural time, invading time, concentration of bacteria, total co- cultural time) were studied, to establish a high frequency of genetic transformation system for processing tomato cotyledon explants of B04. Agrobacterium was used for transformation, and then transgenic plantlets with polygalacturonase gene of processing tomato B04 were obtained. The best pre-culturing time was 2 d. The suit pre-cultural time for processing tomato was 48 hours; OD₆₀₀=0.6 was the fitful bacteria concentration for invading; and the time for invading was 10 minutes; the explants and the bacteria had been best co-cultured for 48 hours. By PCR analysis, 9 plants were positive in 41 plants, and the rate of transformation was 22% . The results proved that the foreign genes had been integrated into B04 processing tomato.