SO

2

and NO emitted from coal-fired power plants have caused serious air pollution in China. In this study

a test system for NO oxidation using O

3

is established. The basic characteristics of NO oxidation and products forms are studied. A separate test system for the combined removal of SO

2

and NO

x

is also established

and the absorption characteristics of NO

x

are studied. The characteristics of NO oxidation and NO

x

absorption were verified in a 35 t·h

-1

industrial boiler wet combined desulfurization and denitrification project. The operating economy of ozone oxidation wet denitrification technology is analyzed. The results show that O

3

has a high rate and strong selectivity for NO oxidation. When O

3

is insufficient

the primary oxidation product is NO

2

. When O

3

is present in excess

NO

2

continues to get oxidized to N

2

O

5

or NO

3

. The removal efficiency of NO

2

in alkaline absorption system is low (only about 15%). NO

x

removal efficiency can be improved by oxidizing NO

x

to N

2

O

5

or NO

3

by increasing ozone ratio. When the molar ratio of O

3

/NO is 1.77

the NO

x

removal efficiency reaches 90.3%

while the operating cost of removing NO

x

per kilogram is 6.06 USD (NO

2

).