The invention discloses a device and a method for altering filter coefficients used in a palarization multiplexing optical coherent receiver. The device comprises a controlling unit, a switching unit and a new coefficient obtaining unit, wherein the switching unit is connected between a first filter coefficient updating unit, and a first filter unit and a second filter unit; the new coefficient obtaining unit produces new filter coefficients for the first filter unit and the second filter unit according to filter coefficients output by a second filter coefficient updating unit; and the controlling unit is used for producing a control signal, and the control signal is used for controlling the switch of the switching unit. When receiving the control signal, the switching unit disconnects the output of the filter coefficients from the first filter coefficient updating unit, and transmits the new filter coefficients from the new coefficient obtaining unit to the first filter unit and the second filter unit, and then recovers the filter coefficients from the first filter coefficient updating unit and outputs the filter coefficients to the first filter unit and the second filter unit.