Picea mongolica, P. meyeri and P. koraiensis as research objects, the genomic DNA of P. meyeri and P. koraiensis were used respectively as the probes to hybridize with the midchromosomes of P. mongolica by the Genomic In Situ Hybridization (GISH) to study the genetic relationship among the three Picea species, and demonstrate the origin of the P. mongolica. In this study, our results show that: (1) the chromosome numbers of all three Picea species were 2n=24 and the karyotype type was 1A, and most of the chromosomes were subcentral centromere. The As.K% of P. meyeri and P. koraiensis were 57.78% and 57.64% respectively, which were lower than that of P. mongolica (58.75%). (2) The 14 chromosomes of P. mongolica showed obvious hybridization signals using P. meyeri genomic DNA as a probe, the stronger signal sites were mainly concentrated in the kinetochore domain, secondary constriction and short arms of the chromosomes. The obvious hybridization signal appeared on 12 chromosomes of P. mongolica using the P. koraiensis genomic DNA as the probe, the stronger signal was mainly located on the kinetochore domain, secondary constriction and long arms of the chromosomes, and the hybridization signal distribution range and intensity were weaker than that of P. meyeri. Therefore, our study shows that the genetic relationship of P. mongolica and P. meyeri were closed than that of P. koraiensis. Then, it was the first to prove that P. mongolica can not be produced by the hybridization between P. meyeri and P. koraiensis.