Gene type, transformation time and plasmid DNA density in pollen-tube pathway were investigated by wheat varieties Xinong 1376 and Zhong 13 as the transformation receptor and pCMLA35-1 plasmid which carried leaf senescence-inhibition gene PSAG12-IPT as the vector. The results showed that plasmid DNA density was correlation to the ratio of seedset significantly but gene type and transformation time was not. With plasmid DNA density increasing in the range of 0~700 ng/μl, the ratio of seedset could be reduced correspondingly. The difference was significant in plasmid DNA density of 300 ng/μl and 500ng/ul and quite in 700ng/μl. The transformation ratio of different gene type was not same because of the different transformation time and plasmid DNA density. The suitable transformation time and plasmid DNA density for Xinong1376 was 40~80 min and 300~500ng/μl and transformation ratio was highest with treatment of 500ng/μl×40 min. However, the suitable for Zhong 13 was 80~120min and 300ng/μl.