In order to overcome the disadvantage of testing deterioration degree of ancient silk, by analyzing ultimate strength and designing mechanism, circuit, software, a new type of tensile strength meter was developed for ancient silk measurement, a meter was made use of weighing precision and recording exhibitory functions of the electronic scales, combined with mechanical parts of speed-controlling, strength-controlling, and sample-securing. The testing showed this tensile strength meter could measure ultimate strength of ancient silk well. This meter provides fine measurement for quantitatively setting out the aging degree of ancient silk.