For detailed research on wavelength suppression of etalon in intracavity frequency doubling laser，the fused quartz F-P etalon is inserted in the intracavity of all-solid-state frequency doubling laser，and theoretical analysis and experimental verification are carried out.The experiment found that inserted etalon is a kind of wavelength selection method based on the selective loss of the laser line，single wavelength operation can be realized by reasonably controlling angle and thickness and the working temperature of the etalon.Results show that the theory is consistent with the experiment，inserted etalon suppresses different wavelengths SFG，and intracavity noise can be suppressed，but its high loss limits the laser output power.