The invention discloses an underground communication instrument for petroleum logging, and belongs to the field of petroleum geological exploration. The underground communication instrument for petroleum logging comprises a remote transmission data transceiving module, a coding modulation and demodulation module, a protocol discriminator, a signal conditioning acquisition unit and an isolation unit which are sequentially bidirectionally and electrically connected from a remote transmission instrument end to a target instrument end, wherein the coding modulation and demodulation module, the protocol discriminator and the signal conditioning acquisition unit are all bidirectionally and electrically connected with a main control logic unit, the main control logic unit is further bidirectionally and electrically connected with a power supply logic module, one side of the power supply logic module is unidirectionally and electrically connected with the remote transmission instrument end, and the other side of the power supply logic module is unidirectionally and electrically connected with a power driving module and the isolation unit; the main control logic unit controls the working sequence and logic of the data stream, and at the same time controls the main control logic unit to generate corresponding power supply types, and the power supply types are transmitted to the target instrument end through the power drive module and the isolation unit. Different types of downhole measuring instruments can be matched to a standardized remote transmission instrument for use, so that alarge amount of equipment purchase cost is saved, and meanwhile, the use flexibility of the downhole instruments is improved.