The analysis is made on the stress state of negative angle thread of wire-line coring drill pipe, the thread stress situation and anti-twist property of CNHT drill pipe used for deep hole wire-line core drilling are calculated based on static and material mechanics. Theoretical calculations and static torsion test were taken on negative angle thread with different taper and tooth height. It is found that theoretical results and test results are very close; by which, the accuracy of the calculation method is determined and the parameters of negative angle thread with strong anti-twist property are optimized and summarized.