Background: Location nuclear imaging systems have been used in many fields

such as astronomical observation

radioactive source monitoring

nuclear development

biomedicine

etc.Purpose: It puts forward much higher requirements of monitoring and control of safety of nuclear facilities and radioactive sources.In this paper

a new portable nuclear imaging system is designed

which can be used in far field imaging.Methods: It uses high resolution detector which consists of LaBr3 crystal and H8500 position sensitive photomultiplier to meet the design requirements of high resolution.In order to acquire the higher radiation collection efficiency

we choose modified uniformly redundant arrays（MURA） as system collimator.It uses the maximum likelihood-expectation maximization（MLEM） algorithms in reconstruction procedure.Results: The test results show that the imaging system can image the far field radioactive source clearly.The field-of-view of our system can achieve the design goal: ±10° ±20°

and its resolution can be variable among 0.923° 2.038°.Conclusions: It can meet the design requirements of resolution and FOV very well.This radiation imaging system can achieve miniaturization and portability radiation imaging robot which is suited for the long-range control.