The paper summarized the deep drilling construction experience in complex formation of Daguzhuang mining section in south Sijiaying iron mine, emphatically analyzed the drilling methods for thick overburden, breaking & leakage, hard and slipping formations and also introduced the technical measures for guaranteeing core recovery in complex formation and the control of oversize deviation of hole deflection from the prospecting line. Based on the deep drilling construction in Daguzhuang mining section, the drilling technical measures for borehole of 1 kilometer and more in complex formation and the attentions & measures for guaranteeing drilling construction quality were put forward.