Kaycie James, 21, of Southampton Township, Pa., was charged with desecration of human remains, evidence tampering and hindering, the phillyburbs.com news website said.
State police are investigating the incident, Police Lt. Brian Polite said Monday.
James and an unidentified man, 24, traveled to Camden, N.J., to buy heroin sometime before his death, and authorities believe he died of an overdose, court documents indicate.
"He died in her apartment and she later drove the body to the (nearby) parking lot of Vincentown Florist," Polite said.
James left the body in the car and fled, without calling for assistance or notifying authorities, court documents said.
An employee of the florist shop found the man in the vehicle Saturday morning and called police, the phillyburbs.com news website said.
A manager of the shop said Monday employees knew nothing about the investigation, or what led James to abandon the car in their parking lot.
Charlize Theron not engaged to Sean Penn 'yet'
Pregnant Mila Kunis wins 'Best Villain' at MTV Movie Awards