For the past decades, the steel industry has focused on the development of new generation advanced high-strength steels (AHSS) to facilitate the steel product with both excellent formability and rigid structure. Nowadays, the 3rd generation AHSS have been extensively studied for commercialization. Among the candidate alloys, the medium-Mn steels with lean alloy composition (i.e., Mn < 12 wt%, C < 0.3 wt%, etc.) have received significant attention owing to its reasonable materials cost and good mechanical responses. The corresponding steel could reveal the two-phase microstructure with plentiful retained austenite after annealing at intercritical region, leading to the high strength level and ductility. Meanwhile, according to the processing routes (e.g., hot rolling plus annealing, cold rolling plus annealing), the two different microstructural morphologies could be obtained: laminate and globular structures. In the present review, the contribution of two different microstructural morphology on the mechanical properties were systematically summarized.