The invention relates to a lithium ion battery electrolyte and a lithium ion battery. The lithium ion battery electrolyte is prepared from the following components by mass percent: 68%-78% of an organic solvent, 8%-12% of lithium salts, 8%-12% of an inorganic film formation additive, 1%-3% of a stabilizing additive, 2%-4% of a conductive additive and 2%-5% of an overcharge protection additive, wherein the lithium salts include lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium difluoroborate and lithium bisoxalatoborate, and the molar ratio of lithium hexafluorophosphate to lithium hexafluoroarsenate to lithium difluoroborate to the lithium bisoxalatoborate is (3 to 8) to :(5 to 9) to :(1 to 3) to :(4 to 7). The lithium ion battery electrolyte has good stability, high conductivity and high safety.