LBlock is a lightweight block cipher designed by Wu Wen-ling and Zhang Lei in ACNS 2011. In this paper, the optimal implementation of LBlock encryption algorithm in hardware is studied. Firstly, the same operation is realized in one module, then the main program calls several times to complete the encryption, especially 32 in Block. Secondly, the same register is used in the subcell and key transformation, the cipher round operation and key update is designed in same module, so that it can release the number of the registers and accelerate the speed of implementation. Last, the sub-modules are combined into a complete program, the correctness of Lblock is tested. It can greatly reduce the area of LBlock algorithm by the optimal method, which can meet the application requirements of smaller chip area and provide reference for the further application of IOT encryption.