为研究直接甲醇燃料电池（Direct Methanol Fuel Cel， DMFC）在全球统一轻型车辆测试循环（Worldwide Harmonized Light Vehicles Test Cycle， WLTC）和中国轻型汽车测试循环（China Light Vehicle Test Cycle， CLTC）两种不同工况下的性能退化特征，采用极化曲线、等效电路模型和弛豫时间分布（Distribution of Relaxation Times， DRT）相结合的方法，利用电化学阻抗谱计算出DRT波峰的变化，分析DMFC的性能退化特征。结果表明：WLTC工况的衰退要大于CLTC工况。两种工况下，传质过程阻碍都对DMFC性能退化起主导作用；WLTC工况下的传质过程阻碍变化率为2.39 m Ω/h，CLTC工况下的传质过程阻碍变化率为0.764 m Ω/h；氧还原反应阻碍不受工况影响。在CLTC工况下，其显著的动态波动性和丰富的瞬态工况对质子传输构成了较大阻碍，有效降低了膜结合水含量。但其对传质阻碍的影响较小，促进了氧气扩散速率的提升。根据氧还原反应阻碍的弛豫时间分布，建立了一个燃料电池退化模型用于表征DMFC的健康状态。为DMFC运行中的健康状态评估提供了参考。

To investigate the performance degradation characteristics of direct methanol fuel cell (DMFC) under two different operating conditions, namely, the worldwide harmonized light vehicle test cycle (WLTC) and the Chinese light vehicle test cycle (CLTC), we adopt a combination of polarization curves, equivalent circuit models, and the distribution of relaxation times (DRT) to analyze the performance degradation characteristics of DMFC. The changes in each polarization process of DMFC are explained by calculating the DRT from EIS according to the evolution of the waveforms. The results show that the degradation of WLTC condition is greater than that of CLTC condition. Under both operating conditions, the obstruction of the mass transfer process hindrance plays a leading role in the performance degradation of DMFC; the rate of change of the mass transfer process hindrance is 2.39 m Ω/h under the WLTC operating conditions and 0.764 m Ω/h Under the CLTC operating conditions; the oxygen reduction reaction hindrance is unaffected by the operating conditions. Under CLTC operating conditions, its significant dynamic fluctuations and abundant transient operating conditions pose a great obstacle to proton transport, thereby effectively reducing the membrane-bound water content. In comparison, it has less impact on the mass transfer obstruction, and thus promotes an increase in the rate of oxygen diffusion. A fuel cell degradation model is built to characterize the ageing state of DMFCs based on the distribution of relaxation times hindered by the oxygen reduction reaction. It provides a reference for the health state assessment and optimization in DMFC operation.