Silicon photomultipliers (SiPMs) are widely used in both high energy physics and medical physics due to their high gain, excellent timing resolution, low operating voltage and insensitivity to magnetic fields. This paper presents a system containing a 64 channel frontend electronics package integrated with a temperature compensation circuit and a light emitting diode (LED) driver circuit for gain stabilization and calibration. The system also has a field-programmable gate array (FPGA) programmed data acquisition system which can simultaneously read 8 frontend cards and provide a programmable high voltage (40-100 V) for the SiPMs. The system has been used in the electromagnetic calorimeter (ECAL) of the positron electron balloon spectrometer (PEBS), a collaboration between Switzerland, Germany, the USA and China with good results in a beam test at the European Organisation for Nuclear Research (CERN). The high-density, multi-channel SiPM readout system can adjust the detector operating voltage on each specific channel with a precision of up to 4 mV and the gain variance is less than 2% after adjustments. This system provides efficient utilization of SiPM in particle-track detectors and calorimeters.