Based on force analysis of key weeding components, 3ZS-150 paddy weeding-cultivating machine which could remove the weeds between seeding lines and inter-rows was designed. The machine motive power from the transplanter and equipped with the spring-tooth cutterhead、inter-row weeding hoe. The field performance testing showed that when the average cultivating depth was 31mm, the cutterhead rotation speed was 186～190r/min, and the forward velocity was 0.35m/s, the average cleaning rate was 80.46%，the injury seedling rate was 4.76%.