Thalli from a brown alga Undaria pinnatifida were soaked by CaCl₂ solution with different concentration and time at 4℃, the effect of CaCl₂ solution on efficiency and influorescence emission spectra of chloroplasts were examined. The results show that the efficiency of collected chloroplasts is increased markedly after soaking in CaCl₂ solution. According to the results of collected efficiency and characteristic of influorescence emission spectra at room temperature of chloroplasts, it was suggested that soaking in the 0.2 mol/L CaCl₂ solution for 10 min is optimum. Under this condition, the efficiency of collected chloroplasts is as 5 fold as control group, and the characteristics of chloroplasts obtained by CaCl₂ soaking are similar to that of traditional method.