Abstract: LC-MS/MS was applied to the determination of 10 antibiotics in swinery waste water with solid phase extraction. The water sample was acidified to pH 2.5 to 4.0 with HCl, and enriched by passing through Oasis HLB SPE column. The column was eluted with methanol. For LC separation, aglient eclipse XDB C18 column was used as stationary phase, and the mixture of 0.1% (φ) formic acid solution and acetonitrile mixed in different ratio was used as mobile phase in gradient elution. ESI+ and multi-reaction monitoring were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the 10 antibiotics were kept in definite ranges. Detection limits (3S/N) found were ranged from 0.03 to 3.5 μg·L-1. Values of recovery found by standard addition method were in the range of 53.2%-104%, with values of RSD′s (n=6) in the range of 0.5%-6.3%.