The accurate measurement of displacement and load in the oil well dynamometer diagram is the need to achieve energy saving, efficiency and stable production. Wherein, the displacement signal is calculated from the acceleration signal in the dynamometer. Theoretically, the acceleration signal can be integrated by two time-domain integrations to obtain the displacement signal. However, the noise and direct-current（DC）components in the time-domain signal would produce a drift-type principle error after two integrals. In order to solve this problem, this paper has proposed a frequency domain integral-based displacement solution method. Meanwhile, this paper has expounded the principle of frequency domain integration and analyzed the possible sources of error of the obtained results. An evaluation model was proposed experimentally verified. Test results indicated this method can be used to improve the accuracy of displacement measurement. This research has important implications for improving the economic benefits of the oil field.