Silicon microelectrode arrays (Si MEAs) have great potential in recording of neural activity; the biocompatibility of silicon nitride has gained much attention as a part of Si MEAs. In this study, we used alternating polycations, polyethyleneimine (PEI), and polyanions, gelatin, to fabricate multilayer films built up by LbL deposition on silicon nitride wafers. Then the samples surfaces were characterized by contact angle system and atomic force microscopy (AFM). The amount of proteins adsorbed on silicon nitride and modified silicon nitride were measured by a modified Coomassie brilliant blue (CBB) protein assay. Cell culture results showed that the modified silicon nitride could increase the adhesion ability of the hippocampal neurons.