Abstract: In order to improve the signal transmission performances of the wireless communication system in the mine roadway, an adaptive spread spectrum modu lation method was provided.Based on the multi-carrier code division multiple access (MC-CDMA)，an adaptive modulation mechanism was added, according to the sign al noise ratio dynamicly adjust base band modulation method of the communication channels in the mine roadway.Based on the bit error rate limit given, an interconver sion signal noise ratio limit between the different modulation modes was determined for the wireless communication system of the mine multi-carrier code division multi ple access when the adaptive modulation was applied.The simulation was applied to analyze the bit error rate performances of the wireless communication system whe n the adaptive modulation was applied.The simulation results showed that under the condition to ensure the certain performances of the system, the spectrum efficiency of the wireless communication system of the mine multi-carrier code division multiple access could be obviously improved when the adaptive modulation was applied.