A Double Data Rate (DDR) gating method is applied to a memory controller of an associated DDR gating apparatus. The DDR gating method includes: outputting from the memory controller an outward clock signal to a memory, and receiving from the memory a backward clock signal corresponding to the outward clock signal, wherein the backward clock signal is utilized as reference for a data read operation of the memory controller with respect to the memory; and providing an input stage of the memory controller with a reference signal to generate, through single ended receiving of the input stage, gating-related information for performing gating when sampling the backward clock signal, and lengthening time of a preamble of the backward clock signal with aid of the single ended receiving of the input stage, for increasing a detection margin of the preamble.