The preparation and calibration of 1 mol / L hydrochloric acid standard titration solution was described in accordance with the requirements of GB / T601-2002"the preparation of chemical reagents standard titration solution", the main source of uncertainty in the calibration process was analyzed and was the uncertainty of the final calibration result evaluated based on JJF1059-1999 "Evaluation and Expression of Uncertainty in Measurement". The results show that combined standard uncertainty is 0.085 4% obtained by evaluation of uncertainty components, and the expanded uncertainty is 0.001 7 mol / L when 1 mol / L hydrochloric acid standard titration solution is calibrated .