Objective To reduce fluctuation range of coating thickness and enhance stability of wave absorbing performance. Methods Air assisted air less spraying coating technology was selected through data analysis, which integrated the advantages of air spraying coating technology and air less spraying coating technology and improved nozzle to realize accurate control of technical parameters, such as spraying flow and spraying range; coating experiment and wave absorbing performance test were carried out to optimize coating parameters. Results The improved nozzle using air assisted air less spraying coating technology had spraying range in 5～30 mm. When spraying for 5 times with 20~24 min every time, the obtained wave absorbing coating surface was smooth without large grain of diameter larger than 50 μm; thickness fluctuation per unit area of coated 2 mm coating decreased from 200 μm to 60 μm, which reduced the decrease of wave absorbing performance from 5 dB to less than 2 dB. Conclusion The accurate thickness coating technology for wave absorbing coating can adjust spraying according to the form and structure of the reference plane to be coated, and realize even spray coating of wave absorbing coating, which greatly improves the coating quality of wave absorbing coating.