Abstract: Wheat straw Nongda 211 and corn stalk Nongda 108 were chosen in order to decrease compress energy requirements and to optimize compression technology. Aimed to simulate the actual conditions of biomass straws baling, “open compression” were experimentally explored with wheat straws and corn stalks in the self-made cylinders by universal testing machine INSTRON 3367. Specific energy requirements for straws were taken into consideration under different moisture contents (15%, 35% and 55% for wheat straws, 25%, 45% and 65% for corn stalks) and frequencies (0.5/min, 0.75/min and 1/min). Study discovered that specific energy requirements of wheat straws were smallest at 55% moisture content and 0.5/min frequency, and ones of corn stalks were smallest at 65% moisture content and 0.5/min frequency under “open compression”. Results shows that moisture content and frequency significantly affected specific energy requirements for wheat straws and corn stalks compression, and specific energy requirements decreased with an increase of moisture content and with a decrease of compression frequency.