Objective To investigate the effect of progressive decompression on neurological function, long-term prognosis and complications in patients with severe craniocerebral injury undergoing modified large trauma craniotomy. Methods From January 2015 to January 2017, ninety patients with severe craniocerebral injury treated in Leizhou Shi People Hospital were selected and were randomly divided into the observation group (45 cases) and the control group (45 cases). The patients in the control group were treated with conventional decompression during the modified large bone flap decompression, and the patients in the observation group were treated with progressive decompression in the modified large bone flap decompression. The Glasgow Coma Scale (GCS) was used to evaluate the degree of damage before treatment and at 1d,3d,5 d,7d,14d, 30d after treatment,the intracranial pressure was monitored before treatment, at the surgical end, and at 1 d, 3 d, 5 d after surgery, the Glasgow′s prognostic score (GOS) was evaluated at 3 months after treatment. the neurobehavioral cognitive state checklist score ( NCSE) and the daily living ability score ( Barthel index ) were performed at 6 months after the operation, and the incidence of postoperative complications was recorded. Results The GCS scores of the observation group and the control group at 3d after treatment were respectively (5.70±0.82) points and (5.05±0.70) points], at 5d after treatment were (7.45±1.12) points and (5.81±0.82) points, at 7d after treatment were (9.38±0.52) points and (6.64±0.65) points, at 14 d after treatment were (10.31±0.79) points and (7.86±0.53) and at 30 d after treatment were (12.79±1.03) points and (10.13±1.31 points),which significantly higher than those before operation ((4.11±0.40), (4.15±0.42) points)(P＜0.05), and the scores of the observation group were significantly higher than those of the control group at each time interval ( P＜0.01). The intracranial pressure in the observation group and the control group were (26.64 + 3.02) and (29.79±2.57) mmHg respectively, (22.88±2.49) and (26.03±3.75) mmHg respectively at 1d after operation, (17.36±1.73) and (24.40±3.07) mmHg at 3d after operation.(14.20±1.18)mmHg and(21.06±2.64)mmHg at 5s after operation, All of them were significantly lower than that before operation (( 31.36 + 4.30) , ( 31.30 ±4.11) mmHg) (P＜0.05), and each time of the observation group was significantly lower than that of the control group (P＜0.01). The good recovery rate of the observation group was 22.22%(10/45), which was significantly higher than that of the control group (6.67%(3/45)). The difference between the two groups was statistically significant (χ2＝4.406, P＜0.05), the plant survival rates in the two groups were 4.44%(2/45) and 20%(9/45) respectively, the mortality rates were 13.33%(6/45) and 31.11%(14/45) respectively, and the two groups had statistical significance.(χ2＝5.050, 4.114, P＜0.05).The NCSE of the observation group and the control group were (69.24±8.42) points and (51.57±6.35) points at 6 months after operation, and the Barthel index was (76.97±5.57)points and (68.24±6.02)points respectively. The observation group was significantly higher than the control group ( t＝10.524, 8.713, P＜0.05). The total incidence of complications in the observation group was 24.44%( 11/45), which was significantly lower than that in the control group (60%) (27/45), and the difference was statistically significant (χ2＝11.660, P＜0.05). Conclusion It is more valuable to use progressive decompression in modified large bone flap decompression for severe craniocerebral injury, which can effectively protect the nerve function, reduce the incidence of complications in the perioperative period, and improve the effect of long－term prognosis.