Wireless reprogramming approach of sensor node is a requirement for flexible configuration and update. Considering the communication overhead and the program overhead,this paper presents a novel lightweight wireless reprogramming approach–EasiLWR with the following merits.By comparing the functions of the new program and the old program,the different codes between functions are transferred instead of entire codes.The communication overhead is reduced.Moreover,using the code shift,the parts of program,which need frequently update are stored and implemented in RAM rather than in the internal Flash of microcontroller unit(MCU).This translates to a reduced programming time.The experimental results show the outperformance of EasiLWR.