Nanotechnology is a new booming science, which has leaped huge significant achievements for only short dozens of years, and created so much wealth for human beings. Their usages on environmental security have been ignored by public, however, multiples of evidences have been demonstrated nano-materials would perform different influence upon a variety of organism. Here, this article concerns that situations and challenges to separate or detect the nano- particles contained in the products or the environment. Meanwhile, a case was presented to introduce an available approach to prepare the nano-colloid (nano-TiO2) for environmental risks research. Therefore, it's necessary for the relevance authorities to formulate effective or available detections upon nano-materials. And the key point should be focused on the normalization of nano-materials control and the establishments on environmental risk assessment upon nano-materials, which will finally promote the developments on the fields of nanotechnology.