Walter Farrell, 54, is being held without bail.
The district attorney's office said Farrell was unlawfully carrying a firearm at the time.
The shooting happened just before 10 a.m. near the intersection of Torresdale Avenue and Howell Street.
Officers boarded the bus because they had noticed a man matching the description of someone who reportedly fired a gun in the area in an earlier incident.
Chopper 6: Police officer fires weapon in Wissinoming
Officers pulled their car in front of the bus and boarded the bus. Police said that is when the officers confronted the man and the man pointed his gun at them.
Once outside of the bus, the suspect began firing on officers and the two officers returned fire, police said.
Officer Donald Revill, 37, arrived on the scene to help and got into a struggle with Farrell. At some point he was shot in the arm.
Revill was treated and released from the hospital.