In the southwestern margin of Ordos basin, 6 Cretaceous conglomerate groups were distributed with abundant geology and hydrogeology information. The paper introduced the B5 well in this area about the well structure design and the construction technology, which could be used for prospecting and longterm observation, coring and pumping test. This well construction proved the possibility of multipurpose by a single well and played demonstration functions for hydrogeology survey in Ordos basin.