In order to investigate the effect and underlying mechanism of representative components of green tea and black tea on nematodes （Caenorhabditis elegans） at different temperature，the survival rate of nematodes at 4 ℃ and 35 ℃ were quantified in the presence of 0.25，2.5 and 25 μmol/L epigallocatechin gallate （EGCG） or theaflavin （TF1）. Then，fat content and mitochondrial membrane potentials were investigated in nematodes incubated with 25 μmol/L EGCG and TF at 4 ℃，20 ℃ and 30 ℃ were determined. The results showed that 25 μmol/L EGCG increased the maximum and median lifespan of heat stressed nematodes by 8.15% and 22.44%，respectively，and decreased the maximum and median lifespan of cold stressed nematodes by 20.25% and 17.94%，respectively. 25 μmol/L TF1 had no significant effect on the survival rate of heat-stressed nematodes，but increased the maximum and median lifespan of cold-stressed nematodes by 9.43% and 19.01%，respectively. At 4 ℃，both EGCG and TF1 incubation increased the fat content of nematodes and TF1 incubation decreased the mitochondrial membrane potential of nematodes. At 20 ℃，EGCG and TF1 showed significant lipid-lowering effect and could significantly improve the mitochondrial activity in senescent nematodes after long-term incubation. At 30 ℃，EGCG and TF1 increased the fat content in nematodes. The results indicated that TF1 improves the survival rate of nematodes by promoting mitochondrial thermogenesis rather than fat mobilization under low temperature conditions，whereas EGCG incubation can induce nematode death.