In order to explore the problems and improvement methods of the current production process of 37Mn5 steel for oil casing smelting in a steel mill， in this paper the whole process sampling analysis of two consecutive heats in the industrial production of the steel plant， including metallographic specimen， oxygen and nitrogen rod and refined slag sample， was conducted. After optimization and improvement， the final conclusions are as follows：（1）secondary oxidation occurs in different degrees in the LF refining and VD calcium treatment stage， specially feeding calcium line stage reaction is more violent ， which is easy to cause the secondary oxidation of the liquid steel and increasing of Ds inclusions. By optimizing the refining deoxyoperation， the amount of calcium line feeding is reduced from 1.4-1.7 m/t to 0.95 m/t， and all kinds of inclusions are grade ≤1.5， and the qualified rate is 100%；（2） the composition analysis of refining slag shows that the residue components in the ternary phase diagram are all outside the liquid phase region， which results in poor melting performance and poor liquidity of the refining slag. By increasing SiO

2

in the slag from to 9%-12%， Al

2

O

3

to 25%-30%， and controlling the binary alkalinity at 5-8， it can improve the melting and fluidity of the slag， strengthen the coverage capacity of the slag， and effectively prevent secondary oxidation；（3） compared to the VD stage， the oxygen and nitrogen content in the tundish casting stage is basically stable， but the number of inclusions has been increased to a certain extent， and the growth rate of the inclusions is far higher than the endogenous rate of the inclusion， therefore， the source is from slag rolling， the smooth casting of the tundish shall be kept， at the same time to avoid the occurrence of dropping off slag phenomenon of the ladle.