The purpose of this study is to propose a new detection technology-whole-hole back-pull detection technology, to reduce the cost and increase the efficiency for the current under-anchor tension detection work, and to more effectively face the engineering reality of large detection volume and short inspection period. Based on the principle of traditional back-pulling method, the application mechanism of whole-hole back-pulling detection technology is elaborated through theoretical analysis and formula derivation, and technical optimization is carried out in combination with experimental research to put forward a perfect application method and carry out feasibility analysis. The study obtained the simplified mechanical model and typical test curve of the whole-hole back-tensioning detection technology, and proposed the formula and application method for the detection value of the tension under the anchor according to the regularity of the test curve. The deviation rate of this technique is within 10%, and the influence of the testing operation on the existing under-anchor tension is about 1%, which is feasible to a certain extent. However, there is still room for improvement in this technology, and the accuracy of detection can be further improved from the perspective of detection equipment and environmental impact, which can then be widely promoted in engineering practice.