The effects of different irrigations on photosynthesis rate and rubisco of radish leaves were studied in this paper. The results showed that the photosynthesis rate of the radish leaves with drip irrigation treatment was higher than that with flooding irrigation treatment during the growth of the radish. The photosynthesis rate was very significantly correlative to initial Rubisco activity, total Rubisco activity and Rubisco content. There was an obvious difference (F=0.400416, p0.05) on Rubisco of the radish leaves with different treatment. The Rubisco content was not the only influencing factors but together with the Rubisco activity, to the photosynthesis rate.