"Instances of cyber-theft have harmed our business and threatened our nation's competitiveness," Kerry said at the end of two days of US-China sixth annual Strategic Economic Dialogue (SED) here.
"The loss of intellectual property through cyber (theft) has a chilling effect on innovation and investment," he said.
To Beijing's discomfort, Washington indicted five PLA officials in May for hacking into US companies.
The two sides traded allegations after the leaks by NSA contractor Edward Snowden have alleged widespread US surveillance over Chinese entities.
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"Cyberspace should not become a tool for damaging the interests of other countries," he said.
Notwithstanding US requests, Beijing refused to resume the working group on cybersecurity it folded up after the indictment of PLA officials. It apparently demanded the repeal of the indictments.
The two also disagreed over means to resolve tensions in the South and East China Seas, amid caution from the US that Beijing risks triggering conflict as it presses its claims to large swathes of territory.
But Yang earlier refused to yield any ground and urged the US to "honour its commitment of not choosing sides" in the maritime disputes.
"China is committed to upholding its territorial sovereignty and maritime rights," Yang said.
China's territorial disputes with its neighbours pose major challenge to the US as many of the countries are America's close allies.
The two sides achieved over 90 per cent outcomes from the SED specially on the trade and climate issues, official media said.
Both agreed to launch negotiations on the negative list of Bilateral Investment Treaty (BIT) early next year and concrete actions to cut emissions.
Often accused by US officials and lawmakers of not playing by global rules, China said it will speed up reforms on currency exchange.
Kerry added the two sides had agreed "on the importance and urgency of achieving a denuclearised, stable and prosperous Korean peninsula".