Goal. To improve the efficiency of processing and presenting the results of experimental studies of random oscillatory processes of agricultural machines and machine units. Methods. The basic provisions of higher mathematics, in particular mathematical statistics and variance-correlation analyzes of statistically random processes, were used during the research. Results. To achieve this goal, it is proposed to return the coordinate system with the random process presented in it by a non-stationary mathematical expectation to an angle equal to the angle of inclination of the line approximating this random process. The further algorithm of actions provides recalculation of ordinates of non-stationary random processes in the new (returned) coordinate system. A comparison of the statistical characteristics of non-stationary and stationary processes shows that at the statistical level of 0.05 the null hypothesis about the equality of their mean values (according to Student’s t-test) and variances of oscillations (according to Fisher’s F-test) is rejected. The normalized correlation function of a stationary random process at the same time, in contrast to a non-stationary one, is characterized by its normal course. Conclusions. Based on the conducted theoretical research the new analytical dependence (5) is obtained, the use of which allows lead to a stationary array the linearly non-stationary by mathematical expectation array of data of random oscillating process of agricultural machines and machine units by statistical processing of experimental research results. The adequacy of the developed analytical dependence (5) is confirmed by the acceptable nature of the normalized correlation function of a random oscillatory process reduced to a stationary one.