The present invention relates to the field of communications, and in particular, to a method and a system for dynamically upgrading a chip and a baseboard management controller. The method includes: obtaining an upgrade file that is used for upgrading a chip; upgrading, based on the upgrade file, data in a flash memory that is used for storing data of the chip, and not performing a reset operation on the chip at this time; and when it is acquired through detection that the state of a service system that is connected to the chip is a service idle state, replicating the upgraded data in the flash memory to a random access memory in the chip, and performing a reset operation on the chip. According to the present invention, the availability and maintainability of the system are improved.