Aiming at poor stubble quality, high loss cutting rate and winding leakage for cutting young and small diameter caragana microphylla of rotary cutter, a kind of reciprocating double knife shrub harvester was designed, which using double crank and rocker mechanism with no fast returning characteristic to drive two sets of knives move and cut in opposite direction. The relation between the displacement, velocity and acceleration of the cutter with crank rotation angle was analyzed. And the double-acting blade cutting speed ratio was analyzed and tested. The results showed that it was best to harvest 2 years old caragana microphylla by the machine when the machine forward velocity was 1.0 m/s and cutting speed ratio was 1.6. The fraction defective of stubble height was 2.3%, the broken stubble rate was 3.3%, the miss cutting rate was 2.3%, the recutting rate was 2.7%, and the productivity was 0.38 hm2/h.