The solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry was used to detect and analyze antibiotics in the water of four urban lakes in Xi’an—Hancheng Lake, Xingqing Lake, Nanhu Lake and Tao Huatan. A total of 15 types of antibiotics were detected in the water samples at a concentration between ND-280.16ng/L, of which Sulfamethoxazole (SMX), Sulfamonomethoxine (SMM), Ofloxacin (OFX), dehydrated red Erythromycin (ETM)and Roxithromycin (RTM) are the main types of antibiotics in four lakes in Xi’an; The ecological risk of antibiotics in four lakes was evaluated by Risk Quotients method (RQ). The results showed that the five antibiotics in Tao Huatan were at high risk level. Three antibiotics were at high risk level in Hancheng Lake and Xingqing Lake, and two antibiotics were at high risk level in Nanhu Lake.