Abstract: Objective To investigate the changes of the pulmonary surfactant protein-D (SP-D) in serum and cerebrospinal fluid in children with viral encephalitis (VE). Methods The levels of SP-D in serum and cerebrospinal fluid were detected by a double-antibody sandwich enzyme-linked immunosorbent assay and compared in thirty children with VE in acute and convalescent phases and in 12 children without VE. Results The levels of SP-D in serum and cerebrospinal fluid between groups of VE acute phase and convalescent phase and no VE were statistically significant (F=103.58，118.15, all P<0.01). The levels of SP-D in serum and cerebrospinal fluid in children with VE in acute phase and in convalescent phase were significantly lower than children without VE (P<0.01). The levels of SP-D in serum and cerebrospinal fluid in children with VE in convalescent phase were all significantly higher than those in acute phase (P<0.01). In children with VE, the level of SP-D in cerebrospinal fluid was weakly correlated negatively with the count of nucleated cells. Conclusions SP-D might be involved in the pathogenesis in VE. The detection of SP-D in serum and cerebrospinal fluid has a certain value for diagnosis of VE.