We investigate the following fourth-order four-point nonhomogeneous Sturm-Liouville boundary value problem: u(4)=f(t,u),t∈[0,1], αu(0)−βu′(0)=λ1,γu(1)+δu′(1)=λ2, au′′(ξ1)−bu′′′(ξ1)=−λ3,cu′′(ξ2)+du′′′(ξ2)=−λ4, where 0≤ξ1<ξ2≤1 and λi(i=1,2,3,4) are nonnegative parameters. Some sufficient conditions are given for the existence and uniqueness of a positive solution. The dependence of the solution on the parameters λi(i=1,2,3,4) is also studied.