Since it has excellent tensile strength,the quenching and partitioning(Q & P) treated steel has been widely acclaimed.Some researched is currently being conducted on Q & P steel,but Q & P techniques and related mechanisms have been mostly research based on conventional transformation-induced plasticity(TRIP) steel.This study researches the effect of Mn on the properties of Q & P sheet steel.Two kinds of steel sheet with different levels of Mn content(1.46%Mn and 2.75%Mn) are investigated.After being fully annealed,the steel sheets were quenched to a temperature between Ms and Mf.Allocation treatment then caused the carbon to be partitioned into the remaining austenite.The microstructure and tensile properties were analyzed.The results show that the increment of Mn content can increase the stability of the steel and decrease the sensitivity of the quenching temperature(QT).The results also indicate that increasing the level of Mn can effectively suppress the formation of bainite. Since it has excellent tensile strength, the quenching and partitioning (Q & P) treated steel has been widely acclaimed. Some researched is currently being conducted on Q & P steel, but Q & P techniques and related mechanisms have been mostly research based on conventional transformation-induced plasticity (TRIP) steel. This study researches the effect of Mn on the properties of Q & P sheet steel. Two kinds of steel sheet with different levels of Mn content (1.46% Mn and 2.75% Mn) were investigated. After is fully annealed, the steel sheets were quenched to a temperature between Ms and Mf.Allocation treatment then caused the carbon to be partitioned into the remaining austenite. microstructure and tensile properties were analyzed. results show that the increment of Mn content can increase the stability of the steel and decrease the sensitivity of the quenching temperature (QT). The results also indicate that increasing the level of Mn can effectively suppress the formation of bainite.