Commerce ministers from Thailand and China signed the agreement at the Great Hall of the People after a meeting between Premier Wen Jiabao and Abhisit.
The two premiers officiated at the signing ceremony.
Details of the agreement were not available at press time, but Abhisit vowed before arriving in Beijing to try to attract Chinese enterprises to invest in a new three-year plan worth about 1.4 trillion baht ($40.9 billion) to revive an economy facing its first annual contraction since 1998.
The Thai prime minister, on his first visit to China since taking office in December, is leading more than 100 government officials and entrepreneurs - the largest team he has taken overseas.
In the first quarter of the year, the Thai economy contracted by 7.1 percent, following a fall of 4.2 percent in the fourth quarter of last year, according to the Thai Commerce Ministry.
Ministry figures showed its trade with China fell 25 percent to $11.3 billion in the first five months of the year.
Virachai Virameteekul, from the Thai prime minister's office, said before the visit that Abhisit would explain to Chinese leaders the reasons behind political unrest in the country and assure Beijing that Bangkok was ready to embrace foreign investment.
Abhisit has raised his expectation for bilateral trade from the current annual $40 billion to $50 billion for 2010.
His efforts received a positive response.
"The Chinese government encourages and supports Chinese enterprises to invest in Thailand and join in its infrastructure construction," reads a press release issued by the Foreign Ministry after the meeting.
Zhang Jiuqin, an expert on Thai studies with the Ministry of Commerce, said that while Sino-Thai trade is shrinking, the goal of $50 billion in 2010 will "possibly be reached", given signs of a warming global economy.
Protesters seeking the resignation of Abhisit forced the cancellation of a summit of East Asian countries on April 11 after storming the Pattaya Hotel, where meetings were being held. The Chinese government has advised citizens against visiting Thailand since the incident and 35 per cent fewer Chinese nationals headed for the country in the following two months.
Abhisit will meet National Tourism Administration Director Shao Qiwei Thursday morning. Thai media said he might ask the Chinese side to lift the tourism warning.
About 700,000 Chinese tourists visited Thailand in 2008, accounting for 8 percent of all foreign visitors.
Wang Yuzhu, an expert with the Chinese Association of Asia-Pacific Studies, told China Business News that the Thai prime minister was looking to mend his country's image.
"This trip should help erase the earlier bad image about political instability, which weighed down our trade," Dusit Nontanakorn, chairman of Thailand's Chamber of Commerce, was quoted by Bloomberg as saying.
Abhisit will meet President Hu Jintao on Thursday.