Aim To explore the effect of Li Shui Tiao Zhi capsule (LSTZ) on mitogen-activated protein kinases signal of vascular smooth muscle cells induced by mildly oxidized low density lipoprotein. Methods Serum-containing LSTZ was produced by general serum pharmacology assay method and protein was removed by methanol. LDL was oxidized by incubation with Cu 2+. c-Jun N-terminal kinase (JNK1), extracellular signal regulated kinase (ERK1/2) phosphorylation was examined by Western Blot assay. Results 20% serum-containing LSTZ significantly reduced the phosphorylated JNK1 level, but ERK1 and ERK2 phosphorylation level after mm-LDL-stimulation was not altered significantly. Conclusions The preferential reduction of the activation of the JNK/SAPK signal transduction pathway might be one of the mechanisms for inhibition of VSMC proliferation caused by LSTZ.