A method for generating a de-mapping clock for service data is provided, comprising: receiving a data frame and obtaining a payload value from the data frame; obtaining distribution of valid service data in a certain time cycle according to the payload value in the data frame; generating a data writing clock according to the distribution of the valid service data, performing a homogenization treatment on the data writing clock, and obtaining the data writing virtual clock; comparing a non-gap statistical quantity of the data writing virtual clock with a non-gap statistical quantity of the service clock gap, and generating a de-mapping clock gap according to the comparison result; generating a service clock gap according to the de-mapping clock gap; and performing a phase-locked loop process on the de-mapping clock gap, so as to obtain a recovery clock signal required by a de-mapping process.