The influence of annealingAnnealing on the microstructureMicrostructure and formabilityFormability of 5XCT35XCT3 sheets was systematically investigated, in response to the production requirements of an aluminumAluminum processingProcessing enterprise. The results showed that the Erichsen Index (IE) value and breaking force from the deep-drawing cup test gradually increase with increasing annealingAnnealing temperature during annealingAnnealing at 105–215 °C. When annealingAnnealing temperature is increased into 275 and 345 °C, the IE value and breaking force also increases significantly due to the significant increase in plasticity. At the same time, the maximum thinning rate also gradually increases, and the hardnessHardness of each area of the deep-drawing tested samples is also improved, resulting in an improvement in the sheets’ forming performance. It is mainly attributed to the microstructureMicrostructure remained band-like shape because of the unrecover under the low annealingAnnealing temperature ranging from 105 to 215 °C, and the recrystallization occurred at the high annealingAnnealing temperature of 275 and 345 °C. The three-point and four-point bending testsBending test were carried out to further explore the formabilityFormability of the annealed 5XCT35XCT3 sheets.