It comes ahead of a two-day visit to Wales by Chinese vice premier Hu Chunhua.
China accounts for 2.2% of all Welsh exports but experts believe there is a potential for more.
The agreement to allow beef exports is estimated to be worth around £25m a year for Welsh meat producers.
Welsh exports to China have increased by 36% over the last two years - and it lies 9th in the list of Wales' top export destinations. Machinery and metals accounted for a third of the goods exported.
But agriculture is now expected to benefit. A protocol signed in London will provide "exciting opportunities" for Welsh beef farmers, according to the Wales Office.
China has now agreed to re-open its market for UK beef by the end of the year. It could be worth an estimated £230m for British producers over five years alone. A ban on UK beef imports was imposed in 1996.
More than a third of red meat produced in Wales is exported outside the UK, predominantly to the EU.
Welsh secretary Alun Cairns said: "This agreement demonstrates the growing confidence in our high-quality food and drink in every corner of the world and highlights the growing demand for Welsh beef in dynamic markets worldwide.
"As we leave the European Union, the UK government is determined to open access to new markets, ensuring that Welsh businesses can continue to grow and thrive."
Agriculture minister Lesley Griffiths added: "We remain optimistic that export barriers for lamb to China will also be lifted in the future and we will continue to support this ongoing work, given its significance to the Welsh economy".
The EU is still Wales' biggest export market by far, followed by the United States.
Although China accounts for 2.2% of trade, Prof Nicholas Perdikis of Aberystwyth University's business school said there was a lot of potential to increase this.
"China is growing very rapidly and there's a big market there for goods," he said.
"But in the future, trade relations might be determined by a number of things, in particular the UK's relationship with the US. If the UK wants a trade deal with China it's quite possible the US might either veto that or put certain blocks on how far they would go to trade freely with us."
Engineering company Airbond in Pontypool makes splicing technology for the textile, glass fibre and carbon industries.
Graham Waters, managing director, is very positive about his dealings with China.
"There are certain issues associated with customs and entry but as long as you use the right people - couriers - and find right customers who are honest and ethical, it's very easy to deal with," he said.
His issues come in safeguarding the company's technology from more unscrupulous operators.
"Everybody knows the potential drawback in China is intellectual property copying. There are really good and competent copiers in China - the big companies we deal with perform very ethically but we have visited people who are unashamed copyists and we don't want anything to get near to them," he added.
"The only way we can handle that is to move very quickly in terms of our technology - and by offering one product while developing others for the future. So we move quickly so the copyists waste their time."
Mr Hu, who is responsible for agriculture, will visit a Welsh farm and university during his visit on Wednesday.
Plaid Cymru said it was essential the Welsh Government strengthened links with important trading partners such as China as Wales made its own way on the international stage "as a serious economic force".
But the party's international relations spokeswoman Delyth Jewell said she hoped that First Minister Mark Drakeford would also take the opportunity to raise the issue of human rights, particularly in relation to Hong Kong and Tibet.
Eluned Morgan, international relations minister, told BBC Radio Cymru that China understood Wales' relationship was an honest one.
"They know that we have concerns about human rights," she said. "The debate about Huawei is a live one at this time. We won't step away from the type of beliefs that we have in our country."
Source :- Bbc.com