hey i finally came up with new trick that save my day 
Original Object file Size : 300Mb
Process :
(1) obj-simplify advise by @donmccurdy.
it will reduce some memory and remove unnecessary stuffs.
so after 1’st Step i have 198Mb size of object
(2) now convert gzip format so will reduce to 50-70Mb 
(3) in this step we are going to decompress gzip file after xhr is download that file (note : here in this process of decompress we use pako.js )
(4) now we just load that decompressed data which is already stored in variable is going to be load in three.js using objLoader.parse(…)
(5) boom object loaded successfully