A data transmission method through a retimer (103, 103 1, 103 2, 330) connected between a primary chip and a secondary chip, the method comprising: having the retimer, the primary chip and the secondary chip performing a first link training, wherein said retimer includes a receiving equalization circuit at its input, a sending equalization circuit at its output and data processing circuits; after the first link training is completed, storing, by the retimer in a first storage area, an equalization parameter corresponding to each rate during the first link training, wherein the equalization parameter includes a receiving equalization parameter of the receiving equalization circuit and a sending equalization parameter of the sending equalization circuit, and wherein data stored in the first storage area is not lost when the retimer performs a reset operation; characterized in that the method further includes: receiving, by the retimer, a reset indication, and performing the reset operation according to the reset indication; in a process in which the primary chip and the secondary chip but not the retimer perform a second link training triggered by the reset indication, invoking, by the retimer, the equalization parameter, and transmitting, by the retimer, based on the equalization parameter, a training sequence in the second link training between the primary chip and the secondary chip by by-passing the data processing circuits such that an output of the receiving equalization circuit is used as an input of the sending equalization circuit, to complete the second link training between the primary chip and the secondary chip. having the retimer, the primary chip and the secondary chip performing a first link training, wherein said retimer includes a receiving equalization circuit at its input, a sending equalization circuit at its output and data processing circuits; after the first link training is completed, storing, by the retimer in a first storage area, an equalization parameter corresponding to each rate during the first link training, wherein the equalization parameter includes a receiving equalization parameter of the receiving equalization circuit and a sending equalization parameter of the sending equalization circuit, and wherein data stored in the first storage area is not lost when the retimer performs a reset operation; characterized in that the method further includes: receiving, by the retimer, a reset indication, and performing the reset operation according to the reset indication; in a process in which the primary chip and the secondary chip but not the retimer perform a second link training triggered by the reset indication, invoking, by the retimer, the equalization parameter, and transmitting, by the retimer, based on the equalization parameter, a training sequence in the second link training between the primary chip and the secondary chip by by-passing the data processing circuits such that an output of the receiving equalization circuit is used as an input of the sending equalization circuit, to complete the second link training between the primary chip and the secondary chip. receiving, by the retimer, a reset indication, and performing the reset operation according to the reset indication; in a process in which the primary chip and the secondary chip but not the retimer perform a second link training triggered by the reset indication, invoking, by the retimer, the equalization parameter, and transmitting, by the retimer, based on the equalization parameter, a training sequence in the second link training between the primary chip and the secondary chip by by-passing the data processing circuits such that an output of the receiving equalization circuit is used as an input of the sending equalization circuit, to complete the second link training between the primary chip and the secondary chip.