The invention discloses a realization method for process layer equipment of an automatic system of an intelligent substation with a decoupling effect. According to the realization method, a merging unit and intelligent terminal integration apparatus (PMI) associated with a relay protection function, and a merging unit and intelligent terminal integration apparatus (CMI) associated with a monitoring function are included; the PMI collects alternating current electrical quantity associated with the relay protection function, and converts into a sampling value message which satisfies an IEC 61850 standard for use for equipment associated with the relay protection function; the PMI collects a state quantity or a direct current value signal associated with the relay protection function, and converts into a GOOSE signal which satisfies the IEC 61850 standard for use for the equipment associated with the relay protection function; the CMI collects alternating current quantity associated with the monitoring function, and converts into a sampling value message which satisfies the IEC 61850 standard for use for equipment associated with the monitoring function; and the CMI collects a state quantity or a direct current value associated with the monitoring function, and converts into a GOOSE signal for use for the equipment associated with the monitoring function. By adoption of the realization method, the coupling degree of different functions is realized, so that it is convenient to perform construction and operational maintenance of the substation.