sir i get 77% in 12 standard can i take admission in d.u for b.com

If you are a Genral category I would say a no even Obc category have no chance butnother 2 have chances even ofnyour are a kashmiri migrant then you have a chance.

Hi, admissions to DU is based on the aggregate percentage of your best four subjects and not overall percentage secured in the qualification examination. I'm sorry to inform that with any score below 86%, it's quite ulikely to get admission in DU for B.Com or B.Com Hons. You can use careers360 DU 2019 College Predictor to get a more confirmed answer as cut offs differ every year.
https://university.careers360.com/delhi-university-college-predictor
Good Luck