To observe the expressions of related proteins of serum mitogen activated protein kinase (MAPK) in patients with Budd-Chiari syndrome (BCS) after artificial vascular bypass operation and discuss their clinical significance. Methods In this study, 40 BCS patients (observation group) and 40 healthy volunteers (control group) were collected. The raleted proteins of serum MAPK were tested by Western blot before operation, 3 days and 1 month after operation, and compared between the two groups. Results The expression levels of serum extracellular signal-regulated kinases 1/2 (ERK1/2), P38, JNK and ERK5 in the observation group before operation, 3 days and 1 month after operation were not significantly different from those in the control group (p > 0.05). In the observation group the expression levels of ERK1/2, P38, JNK and ERK5 before operation were not significantly different from those 3 days or 1 month after operation. Compared to the control group, the expression levels of serum P-ERK1/2, P-P38 and P-JNK were higher,while P-ERK5 was lower in the observation group at each time point (p < 0.05). In the observation group, the expression levels of serum P-ERK1/2, P-P38 and P-JNK rised, but the P-ERK5 level reduced 3 days after operation compared to the preoperative levels. Conclusions Artificial vascular bypass operation can increase the expression levels of serum P -ERK1/2, P -P38 and P -JNK, but reduce serum P -ERK5 expression.However, it has no obvious regulatory effect on the total protein expressions.