Water-energy nexus (WEN) is an international hot-spot issue, while more attentions have been paid to the direct nexus effect resulting from production activities. In this context, this study firstly used the multiregional input-output (MRIO) analysis to offer a full spectrum of water and energy usage throughout the whole supply chain in China, considering production-based perspective and betweenness-based and consumption-based perspectives. And then the principal components analysis (PCA) was applied to further target the critical WEN sectors in Chinese's 30 provinces. The results show that: (1) For most of these provinces, the direct WEN pressure caused by production activities can be found in several traditional resource-intensive sectors, especially in S22 (Production and supply of electric power and steam) and S14 (Smelting and pressing of metals). (2) The most critical transmission sectors with WEN pressure was S12 (Manufacture of chemicals and chemical products), followed by S14 in most of these province. S22 was the key transmission center in several provinces, and S7 (Manufacture of textile) in Fujian and Hubei and S10 (Papermaking and printing) in Zhejiang and Hainan should also be highly-concerned. (3) For all of these provinces, the indirect WEN pressure driven by final consumption appeared in S24 (Construction industry). In addition, S16 (Manufacture of general and special-purpose machinery) and S17 (Manufacture of Transport equipment) were the other two key consumption-based WEN sectors in some provinces. Overall, the WEN pressures in Jiangsu were relatively great in China, and S12 in Hubei was the only sector facing great WEN pressure from all three perspectives. Our results can draw implications for regional sustainable development in China.