The incident happened at the intersection of Scotch Pine Drive and Loblolly Pine Drive around 5:15 p.m. Wednesday in Pinewood Acres.
Police say the child was walking home from a friend's house when the suspect approached and threatened to stab the boy unless he handed over money.
The boy turned to run away as the suspect lunged at him with a knife, police said. The child was able to get away and made it back home unharmed.
The suspect was seen getting into a white work van with tinted windows and driving away.
The suspect was described as a black male about 6' to 6'2" tall, weighing 150 to 180 pounds. He was wearing a black jacket with black pants and a black ski mask.
Anyone with information is asked to call Delaware State Police at 302-697-2104.