Spatial and temporal distribution of total phosphorus (TP) is examined in the sediments of a large tidal wetland dominated by Phragmites (reeds P. communis Trin.) reeds in Shuangtai Estuary, Liaoning Province, China. Eight sampling sites were established within the wetland approximately 11 to 24 km from the Liaohe River. These sites were sampled once a month at multiple sediment depth intervals between April and October in 2013 and 2014, which corresponds with the reed’s growth period. An alkali fusion method was used to determine TP in the sediment samples. Sediment TP content of wetland sediments ranged from 0.001 mg·kg-1 to 0.781mg·kg-1, decreased with increase sediment depth, and decreased from southwest to northeast. The TP content reached a maximum corresponding to the fastest growth stage of the reed (June and July), while the minimum occurs in October (i.e., the maturity stage of reeds).