Wang Jiarui’s visit comes a week after the North said it would stay away from the talks for an “indefinite period” and “bolster” its nuclear arsenal.
China is North Korea’s closest ally and has coaxed it back into talks before.
The US renewed its criticism of the North on Friday, calling its drive to have nuclear weapons a “dead end”.
The Chinese envoy, who is head of the ruling Communist Party’s international department, is expected to be in the North until Monday.
Diplomatic sources say Chinese officials were taken aback by North Korea’s claim to have made nuclear weapons, but they have since called for patience and calm and ruled out sanctions.