Abstract: To compare the difference between Ulva prolifera cultured in different reproductive modes,we got the thalli grown from the spores(ST)and that from vegetative multiplication(VT)by using enclosure experiment in situ and then estimated the difference of photosynthetic performance between ST and VT by comparing the growth,photosynthesis and fluorescence parameter of VT and ST.Our results showed that the growth rate of ST was significantly higher than VT by 61.27% and the maximum photosynthetic rate Pmax,photosynthetic efficiency α and P/R of ST were significantly higher than those of VT by 25.33%,14.93%,134.69%,respectively.While the respiration rate and light compensation point for photosynthesis of ST were lower than those of VT by 45.7% and 52.2%,respectively.It showed that ST possessed better growth advantage compared with VT.Relative electron transport rates(rETR)and non-photochemical quenching(NPQ)of VT were significantly higher than those of ST,and had a higher non-photochemical quenching in the high light.These results implied that compared with the thalli grown from the spores,the thalli grown through vegetative multiplication had stronger high light adaptation ability.