TIANJIN, July 4 (Xinhua) -- The Tianjin-Taiwan trade fair opened Thursday in northern China's Tianjin Municipality, highlighting cooperation and communication.

The four-day event attracted about 600 companies from Taiwan, which brought products including food, tea, jewelry and farm produce to the fair, according to Tianjin's Taiwan affairs office.

Liu Jieyi, director of the Taiwan Work Office of the Communist Party of China Central Committee and the Taiwan Affairs Office of the State Council, said there were over 4 million cross-Strait visits in the first five months, up about 10 percent year on year.

He said the mainland will offer thousands of internship opportunities for Taiwan compatriots this summer.

Chiang Hsiao-yen, former vice chairman of the Chinese Kuomintang Party, said the mainland has done a lot to protect the rights and interests of Taiwan business people, who in turn have made contributions to the economic development and vitality of the mainland.

People of both sides across the Taiwan Strait belong to the same family and they should cooperate, Chiang said.

Zhang Yanmei, assistant vice president of Xiabuxiabu Catering Management (China) Holdings Co., Ltd., said many Taiwanese employees at her company have benefited from the "31 measures," a spate of preferential policies for Taiwan compatriots unveiled by the mainland in February.

The 31 measures cover a wide range of fields including industry, finance and taxation, land use, employment, education and health care.

"Our Taiwanese employees now enjoy an even better working environment on the mainland," Zhang said.

Wu Ming-chi, deputy mayor of New Taipei City of Taiwan, said at the fair that New Taipei hoped to further cooperate with Tianjin in fields such as tourism, culture and high technology.

"I have attended a number of trade fairs on the mainland since 2004. The mainland has many opportunities," said Tsai Yi-huei, manager of an aquatic product company based in Taiwan's Chiayi County.

More than 2,300 people from all walks of life in Taiwan have attended the annual trade fair since 2008. The investment fair, which has been held since 2010, has attracted 3.6 million buyers.