Being the deepest small diameter geological core well in Tibet area, Ni-1 is an oil and gas investigation well with the final depth of 2001.1m. The discussion is made on the construction equipments selection, borehole structure design, coring technology, flushing fluid wall protection and treatment scheme for drilling in complex formations, the drilling construction experiences in high altitude area are summed up with the analysis on the existing shortcomings, which can provide some experience for future drilling construction in this area of Tibet.