This engineering project was conducted to study of factor about densified biomass from maize residues to expansion. And durability of cylindrical biomass after compression and a 9 mm is diameter. And weight control before compression on 2 g. The maize residues is corn cob, corn stalk and corn husk (The moisture of about(8%, 14% and 12% respectively)wb.).The particle of maize residues with 2 size were 0.00 to 0.85 and from 0.85 to 1.18 mm.,The pressure used to compression has 3 levels were 150, 200, and 250 MPa. And temperature used to test has 3 levels were room temperature, 60 and 80 °C. The expansion can be measured from the diameter and length after instant compression, 1 hour after compression and everyday to 5 days. The durability can be measured by pellets durability tester.,rotates at 50 rpm for 10 minutes after 5 days with a compression. Found that the expansion and durability of biomass after compression