Abstract: The effects of different technical parameters (crimping temperature, annealing temperature, slow cooling temperature) on the solid solution carbon content and bake hardening properties of ultra-low carbon bake hardening (ULC-BH) steel were studied by internal friction instrument and tensile testing machine. The results show that the crimping temperature has little effect on the solid solution carbon content and bake hardening value (BH₂ value) of the ULC-BH steel. With the increase of annealing temperature (780-840 ℃), the solid solution carbon content and BH₂ value of ULC-BH steel gradually increase, and the increase of solid solution carbon content is 2×10^-6-3×10^-6. With the increase of slow cooling temperature (650-710 ℃), the solid solution carbon content and BH₂ value of ULC-BH steel gradually decrease, and the decrease range of solid solution carbon content is about 1.5×10^-6.