China has remained the largest trading partner of the Association of Southeast Asian Nations (ASEAN) for 13 consecutive years, a commerce official said Monday.

Trade between China and the ASEAN reached 544.9 billion U.S. dollars in the first seven months of this year. It is up 13.1 percent year on year, accounting for 15 percent of the country's total foreign trade, said Li Fei, assistant commerce minister of China, at a press conference.

As of the end of July, the cumulative two-way investment exceeded 340 billion U.S. dollars, Li said.

Meanwhile, Chinese companies have been making steady progress in contracting infrastructure projects in ASEAN countries, with a cumulative turnover of over 380 billion dollars by the end of July.

China will roll out measures, including professional online and offline trade matching and investment coordination services, to facilitate cooperation with ASEAN amid the upcoming 19th China-ASEAN Expo, said Li.

Preferential measures in areas including customs clearance, transportation, purchasing, and duty-free services will be provided for commodities to be exhibited from ASEAN countries.

The 19th China-ASEAN Expo will take place from Sept. 16 to 19 in Nanning, the capital of south China's Guangxi Zhuang Autonomous Region.