Nostoc flagelliforme is a terrestrial blue-green alga of great food and herbal values. However, its resource is being over-exploited and is diminishing. On the basis of reviewing previous researches on the biology of N. flagelliforme, the dependency of the photosynthetic recovery of N. flagelliforme on light, the influence of CO_2, light and watering on its growth, and the effects of salinity on its photosynthesis were investigated from an ecophysiological point of view. The main results are as follows: 1) The photosynthetic recovery of N. flagelliforme by rehydration was dependent on the availability of light. PS II photochemical efficiency (Fv/Fm) of N. flagelliforme after rewetting was not detected in the dark, but was immediately recognized in the light. The photosynthetic recovery was not only light-dependent and but also influenced by photon flux density. 2) Salinity affected the photosynthesis of N. flagelliforme. Light-saturated net photosynthesis of N. flagelliforme showed the highest value when the alga rehydrated at 20μM NaCl, was reduced at 0μM NaCl and higher levels of NaCl (>20μM). Photosynthesis-saturated Photon flux density (179－269μmol m~(-2) s~(-1)) was maximal at 80μM NaCl. Light compensation points (35-68μmol m~(-2) s~(-1)) increased, but photosynthetic efficiency (α) decreased with increased salinity. Desiccation of rewetted N. flagelliforme lowered its photosynthesis and respiration due to combined effects of water loss and correspondingly accumulated salt. 3) Increased CO_2 concentration enhanced the growth of N. flagelliforme when sufficient light and water was supplied. N. flagelliforme cultured at varied levels of CO_2, light and watering showed the highest relative growth rate at the conditions of high CO_2 (1500 ppm), high light regime and twice daily watering with 31.2% biomass increase in 15 days. The highest relative growth rate was 1.80% per day, about 6 times the lowest. Increased watering exerted insignificant effects on the growth at 350ppm, but significantly magnified its growth at 1500ppm in the hight light regime. In its habitats, N. flagelliforme experiences dry-wet-dry cycles. This study, from the view of photosynthesis and growth, elucidated ecophysiological characteristics during such a process, which would be valued in developing the cultivation technology for this alga.