The invention relates to a DCS (distributed control system) control method and a SMITH controller. The SMITH controller comprises a regulated variable actual value module, subtraction modules, a PID (proportion, integration and differentiation) controller, an actuator M / A station, an actuator output module, a process quantity module, a set value module, a multiplier, a proportionality coefficient modification function device, a multi-order inertia time constant function device, a pure delay time function device and first-order inertia elements. The control method includes procedures of (1), performing a step response test and determining a transfer function model of a controlled object; (2), configuring a DCS by the aid of the transfer function model, corresponding parameter modules and the corresponding function devices; (3), computing parameters of a unit under a load working condition; (4), inputting the parameters to the configuration graph function devices; (5), mounting the configured DCS in a DCS controller of an application system. The DCS control method and the SMITH controller have the advantages that modification parameters of the controller are computed by the aid of the transfer function model, the DCS is configured by the aid of the modification parameters, accordingly lagging in control procedures of a power plant is reduced or eliminated, and the production running control stability is improved.