Using a linked micro-level panel dataset, this paper formally investigates whether Chinese foreign aid stimulates the decisions of energy outward foreign direct investment (OFDI) conducted by Chinese firms. Results show strong evidence that Chinese aid significantly increases the probability of Chinese firms' decisions on energy OFDI in host countries, and the short-term effects are stronger than the accumulative effects. These results are robust with different model specifications. Furthermore, the promoting effects of Chinese foreign aid vary substantially with heterogeneous factors. Specifically, complex and advanced aid forms such as technical aid and export credit, aid for economic infrastructure, energy industry development, and host government finance, as well as the assistance to countries along the Belt and Road, significantly strengthen the promoting effects. This paper provides direct micro-evidence for the promoting effects of Chinese foreign aid on firms' energy OFDI, and also gives policy implications on the aid-driven strategy for stimulating energy OFDI.