The constable, identified as Brijlal, was heading towards Kotwali on his bike when the truck hit him from the rear throwing him off a few metres away, said a police officer.
The driver of the truck, Pramod Kumar tried to flee, but locals caught him and handed him over to the police.
Kumar was arrested after being booked for rash driving and causing death by negligence, police said.
The deceased constable, Brijlal, was posted at Shahdara circle and had joined a few months ago. He was a native of Alwar in Rajasthan and lived with his family in east Delhi's Sagarpur area, police added.