OBJECTIVE To observe the effect of high selenium on insulin signaling pathway PI3K-AKT-mTOR in L02 cells. METHODS One group of L02 cell was treated with different concentrations of selenomethionine(SeMet, 0.001, 0.0025, 0.005, 0.0075, 0.01, 0.025, 0.05, 0.075 and 0.1μmol/L) for 48 h, then cultured with serum-free medium for 4 h and stimulated with 1 μmol/L insulin for 15 min. The insulin signaling pathway(PI3K-AKT-mTOR) was detected by WB. Another group of L02 cell was treated with the same concentrations of SeMet as above for 48 h. The cell supernatant and lysates were collected for the analysis of SELENOP and GPX1, respectively by WB. RESULTS The expressions of P-AKT-(Ser-473), P-AKT-(Thr-308), PI3K and mTOR in L02 cells under high-Se were decreased with the increase of SeMet concentration. The expressions of GPX1 and SELENOP were enhanced with the increase of SeMet. CONCLUSIONS The insulin signaling pathway, PI3K-AKT-mTOR, was damaged in L02 cell under high-Se stress.