Studying the spatiotemporal dynamics of vegetation carbon-water use efficiency and their responses to climatic factors in the context of the “dual-carbon” strategy is essential to enhance the sequestration capacity of carbon in ecosystem. The Google Earth Engine（GEE） platform was used in combination with trend analysis， coefficient of variation， rescaled range（R/S） analysis， and partial correlation methods to investigate the spatiotemporal evolution of vegetation carbon use efficiency（CUE） and water use efficiency（WUE） in the Huaihe River Ecological Economic Belt and the mechanisms of their responses to climate based on MODIS remote-sensing data from 2000 to 2020. The results showed that the multi-year mean value of CUE and WUE in the areas studied was 0.51 and 0.75 g/（m2·mm）. CUE exhibited a fluctuating downward trend， whereas WUE showed a fluctuating upward trend. Spatially， CUE displayed a pattern of higher value in the east and lower value in the west， while the high-value areas of WUE largely coincided with those of CUE， and low-value areas were mainly distributed in the central-northern and central-southern regions. The proportion of areas improved by WUE （32.91%） was significantly higher than that of CUE （13.87%）. R/S analysis predicts that 63.41% of regional CUE will show a positive trend of development in the future， while the proportion of areas with favorable development of WUE will be 36.43%. The CUE was negatively correlated with the air temperature and sunshine duration but positively correlated with the precipitation and moisture in soil， whereas the WUE was positively correlated with the air temperature and negatively correlated with the precipitation， sunshine duration， and moisture in soil. It is indicated that there is significant spatial heterogeneity in the effects of precipitation and temperature.