The invention discloses a remote software upgrading method for an in-situ relay protection device. The method comprises the following steps that a remote terminal reads version information, and an operator decides whether to carry out remote upgrading or not; if the upgrading is needed, the operator transmits programs to be updated and commands to a CPU (central processing unit) 0 in an SOC (system on chip) chip through Ethernet via the remote terminal; after the CPU0 receives software upgrading commands and programs, the software upgrading commands and programs are stored into an RAM (random access memory) to be cached, and in addition, the validity of the upgrading program and the commands can be checked and inspected; the CPU0 writes the upgrading software into an upgrading region in a FLASH, a jumping address table in a BOOT is updated; after the CPU0 receives rebooting commands, the software is rebooted, and the upgraded programs are loaded to the whole SOC chip. The method has the advantages that the program management has high operability, reliability and stability, the program version maintainability is also realized, the requirement of remote on-line system updating of the in-situ relay protection device is met, and in addition, the program version maintenance convenience and speed are respectively improved and accelerated.