Described is the generalized algorithm of making the time-series model describing the parameters of ground complex elements technical state change in time with application of the combined autoregression models - moving average. The generalized algorithm includes the particular algorithms: input of initial information and transformation of time series; identification of stochastic model; preliminary evaluation of stochastic model parameters; selection of optimum stochastic model; evaluation of stochastic model parameters and output of calculation results. Application of the algorithm is most reasonable at organization of the equipment operation, maintenance of which is carried out by actual technical state with checking parameters in the monitoring system.