Heterostructures are classified as a new class of material that can achieve superior mechanical properties. Meanwhile, for industrial use, their formability should be evaluated. In this study, Erichsen forming test was conducted on laminated materials, one of the most used heterostructures in the industry. As a result, high backstress from mechanical heterogeneity enhances the strain hardening exponent, which has a linear relationship with Ericschen Index. Moreover, in damage evolution, interfacial cracking and debonding occurred before sample facture. This serves to crack blunt the main crack propagation in the thickness direction of the sample. Therefore, synergetic hardening and damage evolution from heterostructure results in high formability compared to the rule-of-mixture.