Abstract: With the development of InSb large-scale Infrared Focal Plane Arrays (IRFPA), wet etching process has not met the new technological requirement of IRFPA. A novel wet etching process was expatiated with suitable ratio citric acid/H2O2 as etchant instead of lactic acid/nitric acid in being and assistant etching facility using N2 agitation. The results from comparison and analysis of the experiment clearly indicate that the surface morphology etched by new process, compared with the conventional process, has less lateral etching and mesa trench, more surface uniformity and lower roughness. Otherwise, the electrical properties is improved with lower leak current.