Abstract: According to a comparison of different kinds of accreditation both home and abroad,three principles,homolgizing to other accrediation,high level standards and executable,were advanced to the frame of assessment criteria for the chemicals testing laboratories in compliance with GLP in China.It was considered that the assessment criteria consist of nine parts,i.e. the management rules for the accreditation,accreditation guidelines,accrediation procedure,procedure of extending test items after accrediation,detail rules for assessment,management rules for assessors,application forms for accreditation and assessment report.The details of the criteria composition were expounded.