For agronomic requirements for cotton topping and unsatisfactory profiling effect of the existing machine, a kind of vertical lift type single profiling cotton topping machine was designed. Its structure and working principle were proposed. Central composite test was used on the factors which had effect on profiling effect and quality of topping of the proposed machine. The quadratic regression model of correlation coefficient and walking speed, profile plate and cutting distance, and pump flows were built respectively. The optimal structural and operated parameters were obtained by analyzing the response surface of model. The results showed that, when the travel speed was 0.86 m/s, distance profile plate with cutter was 0.543 m, and the pump flow 4.69 L/min, the best profiling effect and topping quality could be achieved with a correlation coefficient of 0.961. The field test showed that the optimized program was feasible, which provided theoretical basis for design of vertical lift type single profiling cotton topping machine.