Abstract: The 24Mn3Al4/53Mn5Al4 dual lightweight steel composite was fabricated through sequential electroslag remelting, employing a graded strategy where the higher-density 24Mn3Al4 steel (approximately 7.16 g/cm³) was first remelted followed by the lower-density 53Mn5Al4 steel (approximately 6.92 g/cm³).The effect of electrode melting rate (0.000 5-0.001 5 m/s) on the interfacial morphology and bonding strength was investigated through finite element simulation and experimental verification.The results demonstrate that during continuous remelting the system temperature distribution follows the sequence of slag pool (highest)→molten metal pool→crystallizer (lowest), with both the temperature field and molten pool morphology exhibiting axisymmetric U-shaped characteristics and remarkable temporal stability; when the melting rate is increased from 0.0005 m/s to 0.0015 m/s, the molten pool depth shows significant enhancement (the HM/DIn ratio increases from 0.29 to 0.65) accompanied by expansion of the high-temperature zone at the slag/metal interface and widening of the mushy zone; at the intermediate melting rate of 0.0010 m/s, the optimal interfacial bonding strength of 574.89 MPa is achieved, representing 49.7% and 12.2% improvements compared to the values obtained at 0.0005 m/s (384.08 MPa) and 0.0015 m/s (512.61 MPa) respectively, indicating this melting rate parameter is optimal for fabricating the double lightweight steel composite; the excellent agreement between simulation and experimental results (HM/DIn error <10%) validates the reliability of the finite element model and provides crucial theoretical support for process optimization in lightweight steel composite fabrication.