Abstract: Effects of CsCl on germination and metabolism of rapeseeds as affected by CsCl concentration (80、160、320、640, and 960 mg•L^-1) were studied. Results show that CsCl did not have much effect on germination rate (GR), germination potential (GP) and germination index (GI) in the experiments, regardless of its concentration, but stimulated the growth of roots and buds of seedlings when it was low in concentration and suppressed the growth when it was high. What is more, roots of seedlings were more sensitive than buds. With rising CsCl concentration, the contents of protein and proline increased but the activities of dehydrogenase (DH) and peroxidase (POD) decreased in the seedlings, indicating that excessive Cs⁺ may affect the growth and metabolism of the seedlings of rape plant, and the increase in proline content may be attributed to enhance proline synthesis.