The invention discloses a method for prolonging the service life of a flash of ONU terminal equipment and the ONU terminal equipment. The method comprises the following steps: S1, receiving an OAM set message issued by an OLT; S2, temporarily storing the content of the OAM set message in a memory buffer zone (buffer 1); S3, calling a get interface, and temporarily storing the content of a get message into a buffer 2 of the memory; S4, comparing the content of the OAM set message with the content of the get message, if the message contents are different, executing the step S5, and if the message contents are the same, executing the step S6; S5, analyzing the OAM set message, transmitting parameters obtained through analysis to a related module to take effect, and finally storing the parameters in a flash; and S6, sending a response message by the ONU to the OLT. According to the invention, the reading and comparison functions of the OLT issuing configuration parameters can be realized, the comparison result of the OLT issuing parameters and the ONU terminal parameters can be quickly and reliably obtained, unnecessary parameter effectiveness and flash read-write operation are avoided, the flash erasing frequency is reduced, and thus the service life of the flash is prolonged.