Total RNA was isolated from tomato (cv.‘Zhongshu No.4’) leaves using the specific primers designed according to the sequence of cell wall invertase gene in GenBank.A fragment about 416bp was amplified by reverse transcription and polymerase chain reaction.Sequence analysis showed the amplified fragment was the LIN6 cDNA fragment of the cell wall invertase gene.The fragment was inserted into plant expression vector pBinAR between CaMV 35S promoter and OCS terminator to form an antisense plant expression vector pBinAR-aLIN6.Five transgenic tomato plants (cv.MicroTom),identified by PCR and Southern hybrids detection,were obtained through transferring of EHA105/pBinAR-aLIN6.The activity of cell-wall invertase in the leaves of those five antisense plants was found decreasing by 67.9%,13.4%,73.5%,85.6% and 58.0%,respectively.