Abstract: To establish a rapid assay for heat-tolerance of Celosia cristata, seeds and ten-leaf stage seedlings of six cultivars of C. cristata were studied under high temperature stress which increased 5℃ every four hour from 30 to 50℃, respectively. Wilting index, seed germination rate, percentage of seedling establishment, relative electrolyte leakage, malondialdehyde(MDA) content and the activities of superoxide dismutase(SOD) were measured. The results showed that seed germination and percentage of seedling establishment were significantly reduced under high temperature stress, and the most sensitive organ to high temperature stress is terminal bud. Seedlings can be recovered normally in the recovery solution if wilting index is below 4. Under the high temperature stress, both leaf relative electrolyte leakage and MDA increased, while the activities of SOD increased initially but decreased later. Leaf relative electrolyte leakage and MDA increased dramatically after reaching 45℃, and the activities of SOD reached its peak at 45℃. The heat tolerance among 6 C. cristata cultivars was ranked in the order from most tolerant to least tolerant as follows: variety-Centrury Green，Dollbaby, Newlook，Plumosa-Castle，Kimono and Variety-Century Copper. All the physiological indexes measured can be used to assess heat tolerance for C. cristata.

Key words: Celosia cristata, heat-tolerance, assay for heat-tolerance