Phragmites communis phytoliths were extracted from the xerophytic habitat of 12 sampling sites in northeast (NE) China during June–October in 2011 and 2012. The changes of P. communis phytolith concentrations in different temperature zones and growth stages were used to reveal the ecological environmental significance of P. communis phytoliths. The purpose of the study is to provide a scientific reference for quantitative reconstruction of paleoenvironment and studies of phytolith formation. The main phytolith types extracted from the 12 sampling sites and different growth stages were identical; however, the phytolith concentrations differed markedly. In NE China, from the temperate to the warm temperate zone, as temperature increased, the saddle phytoliths, bulliform phytoliths and the silicified stomata concentrations all increased, whereas the lanceolate phytolith concentration decreased. Moreover, in the humid, semi-humid and semi-arid areas, there were different responses of P. communis phytolith concentrations to temperature. Consequently, the spatial results showed that P. communis phytolith concentrations in NE China were closely related to temperature, which enabled inference of the change in temperature from phytolith concentration; however, they were also somewhat affected by humidity. During June–October, the temporal variation results of P. communis phytolith concentrations revealed that there were high lanceolate and bulliform phytolith concentrations in September or October; whereas the saddle phytolith concentration was high in July or August, and the maximum concentration for silicified stomata was in July. These findings may improve the understanding of phytolith formation, and provide useful information to further interpret phytolith assemblages in sediments.