if i choose bank study after 12th does it will help me in future in my IAS studies

yes it can be helpful in some case like current affairs and maths and English

Hi Piyush, Banking industry is one of the robust sectors of the Indian financial system & a career oriented focus on the same will help you shape a rewarding career. After your 12th Std, you can also plan to take up the "Diploma in Banking & Finance" offered by the "Indian Institute of Banking &