The hand grenades were lobbed near the Base on Shahra-e-Faisal Air Base Flyover at about 7:15 pm, during busy traffic hours, the PAF spokesman said in a statement.
"One pedestrian got injured at the exit end of flyover, who was shifted to Jinnah Hospital for first aid," he said.
He said the security agencies were in control of the situation and were carrying out thorough investigation of the incident through all available means including CCTV footage.
"The security of all PAF Air Bases is already on high alert," the spokesman said.
No group has claimed responsibility for the attack.
In May, 2011, militants had attacked the Mehran Naval base which is adjacent to the PAF base.
Around 15 people including security personnel and the attackers were killed in the 15-hour gunbattle that ensued at the naval installation.