The South African timed 46.62 seconds to finish seventh in the 400 meter B race at the Golden Gala meet Friday. He must run a 45.55 to qualify for the Olympics.
His personal best is 46.36.
Pistorius resumed training less than two months ago after a sports arbitration court ruled he was eligible to run in Beijing.
The court overturned a decision by the IAAF that Pistorius' carbon-fiber prosthetics gave him an unfair advantage and that he should be banned from the Olympics and other able-bodied races.
