To understand oil mobilization in germinating seeds, we performed ultrastructural observation and proteomic analysis of endosperm in germinating Jatropha curcas seeds. Results showed that the oil mobilization was initiated during germination, and then the oil was consumed for early seedling development. The significant change in abundance of 50 protein spots during germination indicated that several pathways including beta-oxidation, glyoxylate cycle, glycolysis, citric acid cycle, gluconeogenesis, and pentose phosphate pathway were involved in the oil mobilization.