Improving the seepage control area and flow capacity through hydraulic fracture is an important issue of unconventional gas and oil exploitation. In order to improve the development efficiency of unconventional reservoir, this paper proposes the ultra-high density fracturing technology which satisfies the unconventional reservoir seepage demand. Its core connotation is to use artificial fractures covering the reservoir and realizing extraction of resource in the rock matrix fully. Considering the multi-source characterization parameters of geological and engineering dessert comprehensively, the "approaching ideal solution" principle is employed to obtain initial perforation positions. The models of fracture spacing optimization and limit seepage distance prediction are further applied to optimize cluster spacing 10-14m; Considering the principal stress differences, fracability and rock properties of the perforated cluster matrix comprehensively, the perforation density and hole size parameters are optimized to promote the perforation cluster fractures extension equilibrium. The optimal construction parameters with high displacement (16-18 m3/min), large liquid volume (1440-1696.8 m3/segment), large sand volume (357-431 ton/segment), multi-scale size proppant combination (70/140 mesh, and 40/70 mesh) and slick water are applied to achieve full support for the stimulated area. The ultra-high density fracturing technique applied in JS318 obtains the maximum daily production 25.5×104 m3/d, which is 15 times larger than that of the adjacent well JS317. Field application shows that the proposed technology providing a robust mode to exploit unconventional reservoir.