High data speed and capacity in LTE makes the contradiction between spectrum resources and business capacity more outstanding. This paper first introduces the robust header compression (ROHC) and its application in PDCP sublayer in 3G system. Then, the paper analyses the process and the principles of implementation. Combined with the process of PDCP header compression, the framework realization of ROHC procedure was discussed separately from compress part and decompress part. Finally, an improved decompression algorithm was put forward to enhance the robustness, especially for great quantity of packet loss.