Abstract: When neutron or radon irradiates CR-39 solid state detector, the energy is attenuated, and generating a track on the CR-39, which can be amplified by chemical etching and observed or analyzed by modern microscope. CR-39 is widely used in personal dose monitoring of oil exploration workers, radiation dose monitoring of medical staff and patients in the field of radiation therapy with accelerator and radon levels measurements in the living environments, etc. This article focuses on the CR-39 solid state detector track by chemical etching and the influencing factors are analyzed and introduced.