The invention provides a handoff parameter self-optimization method in a mobile communication system. The method comprises the following steps of: 1) within a handoff performance statistic period T, detecting a late handoff, an early handoff, a handoff to a mistaken cell, a ping-pang handoff and a fast handoff between neighbor cells, and performing statistic of the occurrence times and the handoff times; 2) calculating values of five handoff key performance indicators (KPI) after finishing the statistic period timing; 3) comparing the statistic values of five handoff KPIs with the corresponding target value and judging whether the statistic values are in accordance with the adjustment condition of the handoff parameter, if so, shifting to step four, otherwise shifting to step one; 4) calculating the adjustment amount delta Hlate, ij, delta Tlate, ij, delta Hearly, wrong, ij, delta Tearly, wrong, ij, delta Hpingpang, fast, ij, delta Tpingpang, fast, ij of the handoff parameter Hysij and TTTij; 5) calculating values of the Hsyij and TTTij of the next statistic period; and 6) shifting to step one, performing the handoff performance statistic of the next period. The method enables thehandoff to adapt to the change of the network environment more flexibly, improves the handoff performance and reduces the manual intervention, thereby reducing the network operational expenses greatly.