To investigate if the duration from poisoning to treatment (no treatment period) is related to the prognosis of patients with severe acute organophosphorus pesticide poisoning (SAOPP). One hundred and seventy-four patients with the pre-hospital systematic treatment served as the treatment group while 160 patients going to the hospital by themselves without treatment or rejecting gastrolavage served as the control group. Patients in both groups were treated by gastrolavage, pralidoxime chloride, atropine and other expectant treatment. The duration of no treatment period, death, and severe complication were observed. The time of disappearance of symptoms, the recovery time of acetyl cholinesterase (AChE), atropinization time, atropine dosage, pralidoxime chloride dosage, naloxone dosage, hospitalization days and other targets were also observed. The duration of no treatment period in treatment group [(1.2 +/- 0.3) h] was significantly shorter than that in control group [(2.8 +/- 0.5) h, (P < 0.01)]. The mortality rate in treatment group was 6.32% while that in control group 22.5% (P < 0.01). The incidence of respiratory failure, heart injury, brain injury, atropine poisoning, intermediate syndrome, liver injury in treatment group (12.64%, 5.75%, 8.62%, 1.72%, 4.60%, 5.17% respectively) were lower than those in control group (25.63%, 13.75%, 17.50%, 6.25%, 7.50%, 9.38% respectively, P < 0.05 or P < 0.01). The time of symptoms disappearance, the recovery time of AChE, atropinization time, atropine dosage, pralidoxime chloride dosage, naloxone dosage, hospitalization days in treatment group were significantly superior to those in control group (P < 0.05 or P < 0.01). The pre-hospital systematic treatment can improve the prognosis of the patients with SAOPP, which is worth popularizing and using.