Steel sheet having excellent formability and strain hardening rate

A steel sheet comprising:

• by wt %, 0.10 to 0.16% of carbon (C), 1.0% or less (excluding 0%) of silicon (Si), 1.4 to 2.2% of manganese (Mn), 1.0% or less of chromium (Cr), 0.1% or less (excluding 0%) of phosphorus (P), 0.01% or less (excluding 0%) of sulfur(S), 1.0% or less (excluding 0%) of aluminum (sol.Al), 0.01% or less (excluding 0%) of nitrogen (N), 0.05% or less (excluding 0%) of antimony (Sb), and a balance of Fe and unavoidable impurities;
• and
• bainite having an area fraction of 5 to 25%, 3% or more of retained-austenite, and a balance of ferrite and martensite in a microstructure,
• wherein the steel sheet satisfies the following Relational Expression 1:
• {(C+Si+Al)/((10×(C+Ti+Nb))+(2×Si)+Mn+Cr)/(TS)}×1,000≥0.28[Relational Expression 1]
• where each element represents a weight content, and TS represents a tensile strength (MPa).