The high frequency of multivalents was found in wheat-Agropyron addition line Ⅱ-21-2 which was added (1·4) recombinant P chromosome of A. cristatatum （L.） Beauv. The meioses of 10 different plants of wheat-Agropyron addition line Ⅱ-21-2 were observed. The result showed that there was low-frequency of univalent in all plants and the abnormal chromosome synapses mainly were hexavalents and quadrivalents. 41% pollen-mother cells in 1-7-3 line had hexavalents, while 13% pollen-mother cells in 1-7-7 line had quadrivalents. The analysis of SSR primers from wheat showed that there was polymorphism in wheat genome or P genome of the different plants. Our results suggested that P chromosomes may influence the chromosome synapsis of wheat-Agropyron addition line Ⅱ-21-2 and the molecular polymorphism and recombination of wheat-Agropyron addition line Ⅱ-21-2 may be useful in genetic improvement of wheat.