Background: This research is to take energy spectrum of α particle into consideration in the measurement of radon. Purpose: We aim to find the influence factors of screening particle energy during the process of detector design. Methods: Based on the electrostatic collection radon measurement method

in order to study the influence factors of the measurement such as aluminum foil and air layer

the reasonable radiation source and geometric model are abstracted and calculated with Geant4 software. Results: The best ranges of aluminum foil thickness and air layer thickness are obtained by analyzing their relationship with α energy

the Full Width at Half Maximum (FWHM)

the energy resolution

the distance of peaks and the peaks screening power. Conclusion: With the results adopted above

the energy spectrum device is fabricated. Based on the α energy spectrum sampled in a radon chamber

the validity of this design has been proved. It provides a set of reliable data for the design of radon measuring device with electrostatic collection method.Cited