The opening of China to the world expands continusely, the threats of invasive alien species (IASs) unintentionally introduced into China to agriculture and forestry production and ecosafety are further enlarged, yet few studies have examined the distribution and trends of newly detected IASs with respect to taxonomic categorisation and origin in this country. Here we checked a total of 234 IASs that were unintentionally introduced into China. The study aims to provide information that may help develop better programs for border inspection and postborder early detection. We found 28.[KG-*8]2% and 33.[KG-*8]3% of them were Magnoliopsida and Insecta, respectively; 51.[KG-*8]7% and 24.[KG-*8]4% of them were native to America and Europe respectively. In 1969~2008, the number of newly detected alien insects per decade, and the proportion of insects to all newly detected IASs per decade obviously increased , from 2 species (12.[KG-*8]5%) in 1969~1978 to 17 species (77.[KG-*8]3%) in 1999~2008, respectively. In 1899~2008, the proportion of species native to America was basically stable between 55% and 65%. In 1959~2008, the proportion of insects to all newly detected IASs of American origin per decade increased , from 0 in 1959~1968 to 81.[KG-*8]8% in 1999~2008. These results indicated that in China, insects have become one of the most important groups of newly detected IASs, and North America might still be one of the most important source of invaders.