Climate is the main driver of wetland formation and development, and water gains or losses caused by climate change can pose a serious threat to wetland vegetation. Quantifying the response characteristics of wetland vegetation to wet and dry states is important for wetland ecological restoration. The Naoli River wetland complex is an important freshwater marsh concentration area in China, which is representative of temperate wetlands in the world. This paper analyzed the evolution of normalized difference vegetation index (NDVI) and standardized precipitation evapotranspiration index (SPEI) in the Naoli River Wetland Group Reserve from 2003 to 2023, taking the wetland vegetation in the reserve as the study object. The study period was divided into drought, wet and flood periods according to the dry and wet status, based on which the response characteristics of NDVI to the cumulative and lagged effects of SPEI were revealed. The results showed that from 2003 to 2023, the NDVI of the wetland in the Naoli River Wetland Reserve showed a fluctuating growth trend, with a growth rate of 0.003/10 a, and the meteorological conditions showed a trend from drought to wet. During the drought period, the response time of wetland NDVI in Naoli River and Dongsheng Nature Reserves to SPEI cumulative effect and lag effect was shorter (2 months), and the response time of wetland NDVI in Qixing River and Sanhuanpao Nature Reserves to SPEI cumulative effect (9 months) and lag effect (4-6 months) was longer. During the wet period and the flood period, the wetland NDVI in each wetland reserve was subject to the cumulative effect of SPEI (9 months) and the lag effect (9-10 months, 9-11 months).When the meteorological conditions were mildly dry and wet (-1.15＜SPEI＜1.20 ) and changed from wet to dry, wetland NDVI was positively correlated with SPEI. When the drought and wet intensity were large (SPEI≤ -1.15, SPEI≥1.20 ) and changed from dry to wet, wetland NDVI was negatively correlated with SPEI. This study provide reference value for the in-depth study of the response characteristics of wetland vegetation to meteorological conditions, and provide scientific basis for wetland ecological protection and restoration work.