  The Plastic Scintillator Detector (PSD) is one of the main sub-detectors in
the DArk Matter Particle Explorer (DAMPE) project. It will be operated over a
large temperature range from -$10$ to $30^{\circ}$C, so the temperature effect
of the whole detection system should be studied in detail. The temperature
dependence of the PSD system is mainly contributed by the three parts: the
plastic scintillator bar, the photomultiplier tube (PMT), and the Front End
Electronics (FEE). These three parts have been studied in detail and the
contribution of each part has been obtained and discussed. The temperature
coefficient of the PMT is $-0.320(\pm0.033)\%/^{\circ}$C, and the coefficient
of the plastic scintillator bar is $-0.036(\pm0.038)\%/^{\circ}$C. This result
means that after subtracting the FEE pedestal, the variation of the signal
amplitude of the PMT-scintillator system due to temperature mainly comes from
the PMT, and the plastic scintillator bar is not sensitive to temperature over
the operating range. Since the temperature effect cannot be ignored, the
temperature dependence of the whole PSD has been also studied and a correction
has been made to minimize this effect. The correction result shows that the
effect of temperature on the signal amplitude of the PSD system can be
suppressed.
