Abstract: In strata scries Ⅲ2 of Baobei block, Baolang oilfield, oil reservoir porosity is 12.8%, air- permeability 16.8 ×10-3μm2, formation saturation pressure diffcrence 4.47 MPa, gas -oil ratio 250m3/t, and crude oil shrinkage ratio 38.38％. Whether or not formation pressuremaintenance level is rational is of vital importance to development.Injection-production nodal point analysis and oil well degasification radius calculation show that when formation pressure maintaining at 90％ andinjection - production being under balanced conditions,bottomhole flowing pressure in producers is 18MPa, wellhead oil pressure 3.65MPa; bottomhole flowing pressure in injectors is 46.68MPa, wellhead injecting pressure 24.16MPa, and injection - production relationship is harmonious;degassed radius of oil well is only 1 .7m, but oil rate do not decline grcatly. It is concluded that rational pressure maintenance level in layer Ⅲ2 should be 90°of the original formation pressure.