The method of the stray light suppression in infrared focal plane array dewar is studied. Some purposes and several
design principles of baffle vanes in cold shield are presented. Two configurations of cold shield are proposed to reduce
the effect of stray light on the basis of the configuration of the original cylindrical cold shield. The effects of three
configurations of cold shield on stray light suppression were simulated, compared and analyzed by using the TracePro
software. According to the analyzing results, the two configurations of cold shield proposed are much better than the
original one, and the effect of the cold shield with one baffle vane is close to the other cold shield with two baffle vanes.
The three cold shield were manufactured and assembled in the same infrared focal plane array dewar to be test
respectively. The test results are in accord with the simulation. On account of fine effect on the stay light suppression and
simple making technology, the cold shied with one baffle vane is applied to dewar assembly. The effect of the stray light
suppression and background radiation decrease is improved.