An improved BP neural network algorithm is presented according to original limitations and shortages.The relationship of load vs.deflection of monocrystalline silicon micro-cantilever beam is simulated by this algorithm with MATLAB7.0.The results indicate that the deflection increases with the increment of the micro-cantilever beam length

and decreases with the increment of the width.Moreover

the results of the theory are accorded with that of experiments for the effective load-deflection relationship data.The elastic modulus of the micro-cantilever beam of Si(100) is also evaluated

and the approximation is 153 GPa

which is agreeable with the practice.