This paper is concerned with the existence and uniqueness of positive solution for the fourth order Kirchhoff type problemwhere a > 0, b ≥ 0 are constants, λ ∈ R is a parameter. For the case f (u) ≡ u, we use an argument based on the linear eigenvalue problems of fourth order equations and their properties to show that there exists a unique positive solution for all λ > λ 1,a , here λ 1,a is the first eigenvalue of the above problem with b = 0; For the case f is sublinear, we prove that there exists a unique positive solution for all λ > 0 and no positive solution for λ < 0 by using bifurcation method.