Abstract: Based on water stress treatments in different key growth stages from jointing to mature periods of maize with the method of continuous nowater complementing for a long time, photosynthetic characteristics of spring maize Danyu 39 during the processes of drought of different levels and rehydration were dynamically measured. The response characteristics of the variables associated with photosynthesis including net photosynthetic rate (P_n), transpiration rate (T_r), stomatal conductance (G_s) and intercellular CO₂ concentration (C_i) as well as the photosynthetic parameters such as apparent quantum yield (AQY), maximum net photosynthetic rate (P_nmax), light compensation point (LCP) and light saturation point (LSP) to drought were investigated. The results showed that P_n, T_r, G_s and C_i decreased with the intensified continuous drought stress. In response to the drought, the variables mentioned above were more obvious in tasseling stage than in jointing stage, and T_r was faster than P_n, and C_i was more apparent under low than high light intensity. In addition, the responses of the variables to rewatering after the drought differed markedly and their restoration abilities declined with prolonged drought duration and were weaker in tinseling stages than in jointing stage. Specifically, the P_n of the plant suffering short drought exceeded that of the normal plant under condition of suitable soil moisture after rewatering. Meanwhile, the response of T_r to re-watering fell behind that of P_n and its restoration ability to rewatering after  drought was weaker than that of P_n. The response of C_i to rewatering after drought was more sensitive under high light intensity. Moreover, as the drought was worsened, AQY first increased then decreased; P_nmax diminished constantly with an increasing response speed and its recovery capability to rewatering decreased; LCP and LSP increased and decreased respectively. Furthermore, AQY, LSP, P_nmax and the range of available light intensity used by photosynthesis increased significantly with soil water content (SWC), while a significant negative correlation was found between LCP and SWC.