The invention discloses a non-power failure transmission transformation method for intelligent substation 3/2 wiring reconstruction and expansion. The method comprises the steps: determining secondaryequipment with virtual connection association with a medium switch protection, a medium switch intelligent terminal and a medium switch merging unit before reconstruction and expansion; generating xml files for checking virtual terminal configuration of the secondary equipment before and after reconstruction and expansion; calculating the CRC check code of the check virtual terminal of each secondary equipment set before and after reconstruction and expansion; comparing the CRC check codes of the check virtual terminals of the secondary equipment before and after reconstruction and expansion;checking the consistency between the secondary equipment downloading documents after reconstruction and expansion and the SCD documents after reconstruction and expansion; and performing consistencycomparison between the exported secondary equipment configuration file and the SCD file after reconstruction and expansion and judging whether the transmission experiment is needed according to the results. The transmission transformation is carried out under the condition that the judgment information is consistent for many times through the above judgment process so as to ensure the continuity of power supply.