The 2009 world 800m champion Semenya ran 2:00.72 passing the needed mark mark by 0.28 seconds in an international meeting in Linz, Austria on Saturday, August 1.
The South African middle middle distance runner struggled to hit the qualifying mark due to coaching problems and injury setbacks in the past two years.
She also missed out 2013 world championships and last year's commonwealth games.
Semenya's best 800m mark is 1:55.45 from 2009 world championships final. Her current mark of 2:00.72 ranks her in 48th position in the world this season.
Beijing world championships in athletics will take place on August 22-30.