Abstract: A kind of power saving technique has been developed in order to extend the battery replacement cycle of EM-MWD.With longer duty period,DPPM is employed for signal modulation of EM-MWD to save power.The transmitter and radio frequency circuit of EM-MWD are shut off power during the loner duty period and only powered on for radio emission in pulse phase,which can significantly reduce the EM-MWD transmitter power consumption.Coding block bits and time slot are two key parameters to determine energy saving efficiency and coding efficiency of DPPM.Energy saving efficiency increases with coding block bits,but coding efficiency decreases.Matching the coding efficiency and energy saving efficiency,the optimal block bits number is 3 or 4.Shortening coding time slot can significantly improve coding efficiency,while energy saving efficiency slowly decreases.On the premise of ensuring appropriate bit error rate,three kinds of common time slot were analyzed,which showed that the shorter time slots was favorable for the tradeoff between coding efficiency and energy saving efficiency.Analysis and examples showed that powering off transmitter and radio frequency circuit during DPPM code duty period could significantly reduce the energy consumption and prolong battery replacement cycle.