Abstract: By using upper and lower solution method and topological degree theory, the author studies the existence of multiple positive solutions for clamped beam equation with inhomogeneous boundary conditions, where f∈C(［0,1］×［0,∞),［0,∞)), b>0. The results show that when f satisfies certain conditions, there are countable multiple positive solutions for the problem.

Key words: nonhomogeneous, positive solution, upper and lower solution method, maximum principle