The overall non-uniform gratings were simplified cascading multiple uniform sub-gratings, the effects of three typical non-exponential decays on the output spectrum of Fiber Bragg Grattings(FBGs) were simulated. Simulation results show that the conventional FBG strain sensor is not suitable for anchor axial strain measurement. The structure of FBG strain sensors packaged in thin-walled capillaries was proposed, and the measurement principle and mechanical characteristics were analyzed, the basic formula of capillary material and thickness selection was deduced. The sensor samples were developed with carbon fiber composite materials, and the mechanical tests were carried out. The test results show that the sensors′ performance expectations are achieved. Two FBG strain sensors were pre-implanted into the test anchor, during the tensile process. FBG spectrum occurs no broadening, fission sign, which can meet all the requirements of the prototype cable tests. The relationship between FBG outputs and cable tension are of good consistency, and are of good reproducibility and linearity, which proves that the tension measurement method is entirely feasible.Key words: