The invention discloses an input quantifying ensilage cutter. The input quantifying ensilage cutter is characterized in that a support plate is further connected with a side of an ensilage cutter body, a forage grass inlet which is communicated with a body inner cavity is formed in the support plate, a rolling clamping mechanism which corresponds to the forage grass inlet is obliquely arranged on the support plate, a quantifying rotary drum which corresponds to the rolling clamping mechanism is further connected with an end of the support plate and comprises an outer drum and an inner rotary drum, the outer drum is in the shape of a straight drum, the inner rotary drum corresponds to the outer drum and can rotate in the outer drum, and a conveying drum which is in the shape of a straight drum is arranged in the inner rotary drum. The input quantifying ensilage cutter has the advantages that the quantifying rotary drum can be connected onto the support plate of the input quantifying ensilage cutter, the rotary inner rotary drum is arranged in the quantifying rotary drum, a rotary transmission belt is arranged in the inner rotary drum, elastic compression quantifying rods are arranged on the transmission belt, accordingly, the input quantity of corn straw can be set by the quantifying rods, and the labor intensity can be further improved.