The invention discloses a wind power generation unit low-speed end flexible coupling used for being connected with a wind wheel and a speed increasing device; the low-speed end flexible coupling comprises an active disc and a passive disc which is coaxially arranged with the active disc; the active disc is used for connecting a main bearing of the wind wheel; the passive disc is used for connecting an input shaft of the speed increasing device; and the active disc is connected with the passive disc through at least one flexible transmission chain. The low-speed end flexible coupling provided by the invention can realize that a pure torque of the wind wheel is transferred to the speed increasing device only, greatly lowers the requirement for the coaxiality between the main bearing of the wind wheel and the input shaft of the speed increasing device and can realize automatic uniform load. The invention also discloses a wind power generation unit.