Based on electrohydraulic variable valve train，the negative valve overlap(NVO) strategy was designed and the effect of NVO strategy on gasoline compression ignition (GCI) was studied. By studying the influence of solenoid valve input signal on valve timing，the valve timing was found to change linearly with the solenoid valve input signal and the negative valve overlap strategy was designed. In addition，the repeatability of valve lift curve was verified under the engine ignition condition. The results showed that the fluctuation of exhaust valve lift was slightly larger than that of the intake valve. The maximum fluctuation amplitude of exhaust valve lift was 0.2 mm，its maximum standard deviation was 0.056 mm，and so the repeatability was good enough to meet the requirements. Further, the valve lift slightly decreased with the decrease of valve opening duration. In the end, the influences of intake and exhaust valve timing on the combustion performance of GCI were studied. It was found that the exhaust valve close timing had a great influence on internal EGR rate and a dominant effect on GCI combustion performance.