Objective To design a pedaled negative-pressure aspirator in order to meet the needs of treating the wounded in the field operations. Methods The air is sucked in and expelled by a piston-type device to generate negative pressure. Its materials and structure were reasonably chosen and designed. Results Experimental measurements showed that the pedaled negative-pressure aspirator can generate negative pressure in straw port, which has a suction effect, and the negative pressure value increases with increasing suction time. The pedal type negative pressure aspirator has good hermeticity, and it is easy to produce good effect of negative pressure. Conclusions The aspirator is of small size and low weight, thus convenient to carry and use. When used in the field, it offers a satisfactory effect in the first aid.