A field experiment was conducted in a semiarid area to investigate the response of soil enzyme activities to climate change in a farmland of spring maize where plastic film mulching was used. Open-top chamber(OTC)system was used to control elevated CO_2 concentrations(700 mumol·mol~(-1), marked as OTC+CO_2)during the growing period of maize. At the same time, OTC systems with the current atmospheric CO_2 concentration(marked as OTC)and natural atmospheric CO_2 concentration(control, marked as CK)were also set up. Activities of soil urease, alkaline phosphatase, sucrase, and catalase, at the different growth stages of spring maize(i.e., pre-sowing, sixth leaf (V6)stage, twelfth leaf(V12)stage, silking(R1)stage, milk(R3), and physiological maturity(R6)stage), were measured. The results showed that, compared with CK, OTC treatment decreased the activity of soil alkaline phosphatase by 8.80% at the V12 stage(P<0.05), and increased it by 8.95%(P<0.05)at the R6 stage, decreased the soil invertase activity by 12.65%~21.43%(P<0.05)at the pre-sowing, V6, and R1 stages, but increased it by 17.50%(P<0.05)at the R3 stage, and significantly decreased the activity of catalase at the V12, R1, and R6 stages under OTC. Compared with OTC, OTC+CO_2 treatment had no significant effect on soil urease activity, increased the activity of soil sucrase by 30.18% and 18.37% at the V6 and R3 stages(P<0.05), respectively, and decreased the activity of alkaline phosphatase at the R1 and R6 stages by 8.74% and 6.39%(P<0.05), respectively. In addition, elevated CO_2 increased activity of catalase at the V12 stage, but reduced it at the R3 stage. In conclusion, the effect of elevated CO_2 on soil enzyme activities in spring maize farmland varied with the growth period and the enzyme. Further, under the current experimental conditions, the effect of OTC on soil enzyme activities was more significant than that of elevated CO_2.