The study analyzes the impact of China’s export growth on Thailand’s export by separating the products which are disaggregated by 3-digit SITC, into 9 groups based on the production technology. The analysis consists of two parts. The first part compares Thailand’s export competitiveness with China’s export using the constant market share model (CMS). The study is divided into 3 sub-periods namely, before Thailand’s economic crisis in 1992 to 1997, the recovery period of 1997 to 2002, and the most recent from period of 2002 to 2007. The second part examines the effect of the increased market share of China’s export in the world market on Thailand’s exports using panel data during 1992 to 2007. The study results in the first part show that in all sub-periods Thailand’s export growth relied on the expansion of the world market. Thailand lost the export competitiveness to China in almost all product groups except for automotive products, chemical and besic metal products. The findings in the second part indicate that an increase in China’s export market share on the world market clearly adversely affected Thailand’s exports in the following product groups: primary products, resource-based products, labor-intensive products, low-tech manufactured products, and chemical and besic metal products. However, Thailand’s export were able to grow along with China’s in the product groups of agro-based manufactured products, automotive products, engineering products, and electronic and electrical products. Both parts conclude that unless Thailand improved its competitiveness, its exports would be at a greater disadvantage compared to the Chinese exports.