The research on the propagation ability and plant genetic stability was carried on with the long-term cultured embryogenic cell lines of Liriodendron hybrids which was established in 1999 as study material. The results showed that the embryogenic cell lines kept high frequency regeneration ability after three years, even six years of sub-culture. The genetic stability of the regenerated plantlets had been studied by chromosome numeration and it was found that these somaplants were diploid mostly, while only one of the somaclones regenerated plants with tetraploid karyotype.