The invention discloses a high efficiency storing method for the coding digit of an LDPC coder based on an FPGA. In the method, the coding digit and external information (or channel information) share one storage block, thereby effectively reducing the requirement of the coder to the quantity of the storage resources; and the coding digit and the external information can be withdrawn when reading the storage block. Therefore, a check equation computational unit PCU and a check node update unit CNU can share one group of address information, and the PCU does not need additional address generation units; and finally, the design method of a step thinning production line is adopted to realize process units VNU, CNU and PCU, thereby effectively reducing the key path delay of the coder and providing a necessary safeguard to improve the throughput of the LDPC coder. When realizing the method with the FPGA, the invention not only can save a large number of the resources for respectively storing the digit and the logic resources for generating addresses which are needed by the PCU, but also can improve the throughput of the coders.