Zhang, invited into the tournament as a wild-card entrant, didn't lose her serve against King, who had played through qualifying in reaching the final. All but one of King's six matches prior to the final went three sets.
That may have finally caught up with here against Zhang, who took the first set and then dominated the second set. She won 70 percent of the points overall, losing just five on serve and six when King served.
Zhang swept through the tournament without losing a set. A 6-1, 6-1 win over Yvonne Meusburger in the semifinals Friday put her into her first WTA title match.
King's long week also saw her team with Galina Voskoboeva and finish second in the doubles to Hsieh Su-wei and Peng Shuai. That match, like the singles final, lasted 1 hour, 36 minutes.
King was playing in her second WTA final, but first since she won the PTT Bangkok Open in October 2006.
Zhang collected a first-place prize of $112,000, pushing her career total $980,937. King, who has won more than $3 million in her career, won $56,000 as the runner-up.