In the paper, the protective effect of maslinic acid (MA) on LPS-induced inflammatory response in RAW264.7 cells was investigated, and its inhibition of transcription 3 (STAT3) phosphorylation, a signal transducer and activator, was also explored. NO generation was measured by Griess method. The levels of IL-6, IL-1β and IL-10 were detected by ELISA. The relative expression of iNOS, p-STAT3, p-JAK2 and SOCS3 were determined by Western blot. The release of reactive oxygen (ROS) was evaluated using DCFH-DA fluorescence. Results showed that MA could significantly inhibit the NO generation and the production of ROS. MA also decreased the releases of IL-6 and IL-1β, increased the content of IL-10. The expression of iNOS in LPS-induced RAW264.7 cells was inhibited by MA. In addition, the phosphorylation and the nuclear translocation of STAT3 could be suppressed by MA in dose and time-dependent manner. The phosphorylation of JAK2 was also inhibited by MA, while the expression of SOCS3 could be activated. These results suggested that MA protected against LPS-induced inflammatory response in RAW264.7 cells, and its mechanism was probably associated with the inhibition of the phosphorylation of STAT3.