The invention discloses a telescopic array type portable 
MIMO-SAR (multiple-input multiple-output 
synthetic aperture radar) measurement 
radar system and an imaging method thereof. The 
system comprises a telescopic 
MIMO antenna array, a 
radar transmitting / receiving 
machine, a control and 
processing computer, a liftable antenna frame and the like. The 
system has the advantages in an aspect of meeting field diagnosis and measurement of scattering properties in using and maintenance processes of a low detectable target that firstly, quick detection, positioning and 
imaging diagnosis of an abnormal scattering part of the low detectable target can be realized, that is, an 
MIMO-SAR different from a linear guiderail SAR in mechanical scanning imaging can finish high-resolution two-dimensional imaging of a measured target through one-time or two-time 'snapshot' electric scanning imaging; secondly, the requirement on a target 
test site environment is lowered, that is, guide rails for precision 
mechanical screening measurement do not need to be mounted in a target 
test site, so that the requirement on the site test environment in 
imaging diagnosis and measurement operation processes is greatly lowered; thirdly, the 
antenna array is telescopic, so that 
miniaturization, quick unfolding and folding as well as portability of the measurement 
radar system can be easily realized.