A design method of an optical line termination, OLT, line card applied to enable the OLT line card to be compatible with a 10G Ethernet Passive Optical Network, 10G EPON, and a 10-Gigabit-capable Passive Optical Network, xGPON, characterized by the method comprising: acquiring a first standard signal definition table for a plurality of pins in an optical module corresponding to the 10G EPON and a second standard signal definition table for a plurality of pins in an optical module corresponding to the xGPON; classifying the first standard signal definition table and the second standard signal definition table according to a plurality of functions of the plurality of pins, generating a new standard signal definition table by comparing the differences of signal definitions for the 10G EPON and xGPON optical modules, and enumerating the signals for the pins with the same serial number and different functions for comparison, in case the same pins in the two optical modules have inconsistent signal definitions for enabling different functions, performing signal multiplexing in a new pin definition, and configuring a hop-selecting connection in the OLT line card to implement compatibility with the 10G EPON and xGPON optical modules; and configuring the plurality of functions of the plurality of pins in the OLT line card based on the new standard signal definition table; wherein classifying the first standard signal definition table and the second standard signal definition table according to a plurality of functions of the plurality of pins comprises: comparing a plurality of definitions of the plurality of pins in the first standard signal definition table and the second standard signal definition table through a one-to-one correspondence of a plurality of serial numbers of the plurality of pins; classifying one or more of the plurality of pins having a same serial number and a same function or one or more of the plurality of pins having a same serial number and corresponding functions not affecting each other as a first type of pin, the first the type of pin having a single function definition; and classifying one or more of the plurality of pins having a same serial number and different functions affecting each other as a second type of pin, the second type of pin having at least two function definitions. acquiring a first standard signal definition table for a plurality of pins in an optical module corresponding to the 10G EPON and a second standard signal definition table for a plurality of pins in an optical module corresponding to the xGPON; classifying the first standard signal definition table and the second standard signal definition table according to a plurality of functions of the plurality of pins, generating a new standard signal definition table by comparing the differences of signal definitions for the 10G EPON and xGPON optical modules, and enumerating the signals for the pins with the same serial number and different functions for comparison, in case the same pins in the two optical modules have inconsistent signal definitions for enabling different functions, performing signal multiplexing in a new pin definition, and configuring a hop-selecting connection in the OLT line card to implement compatibility with the 10G EPON and xGPON optical modules; and configuring the plurality of functions of the plurality of pins in the OLT line card based on the new standard signal definition table; wherein classifying the first standard signal definition table and the second standard signal definition table according to a plurality of functions of the plurality of pins comprises: comparing a plurality of definitions of the plurality of pins in the first standard signal definition table and the second standard signal definition table through a one-to-one correspondence of a plurality of serial numbers of the plurality of pins; classifying one or more of the plurality of pins having a same serial number and a same function or one or more of the plurality of pins having a same serial number and corresponding functions not affecting each other as a first type of pin, the first the type of pin having a single function definition; and classifying one or more of the plurality of pins having a same serial number and different functions affecting each other as a second type of pin, the second type of pin having at least two function definitions. comparing a plurality of definitions of the plurality of pins in the first standard signal definition table and the second standard signal definition table through a one-to-one correspondence of a plurality of serial numbers of the plurality of pins; classifying one or more of the plurality of pins having a same serial number and a same function or one or more of the plurality of pins having a same serial number and corresponding functions not affecting each other as a first type of pin, the first the type of pin having a single function definition; and classifying one or more of the plurality of pins having a same serial number and different functions affecting each other as a second type of pin, the second type of pin having at least two function definitions.