Objective To study the protective effect of helmet on human head injury under continuous frontal blast shock wave. Methods A finite element head-helmet coupling model was established to analyze the effects of helmets on biomechanical response parameters such as intracranial pressure and cranial pressure under single frontal blast and continuous frontal blast shock wave. The dynamic changing law of brain tissues in the blast environment was discussed to evaluate the protective performance of helmets on human head. Results In the case of single frontal blast impact, the helmet could effectively reduce intracranial pressure in the frontal lobe, occipital lobe, and parietal lobe by 32%, 38%, and 19%, respectively, as well as peak stress at the rear of the skull. In the case of continuous frontal blast impact, the helmet could reduce intracranial pressure in the parietal lobe and occipital lobe by 36% and 21%, respectively, but its effect on intracranial pressure in the frontal lobe was limited due to the lack of facial protection. Conclusions Compared to single blast shock wave, continuous frontal blast shock wave has a more severe impact on craniocerebral injury due to its long effective effects on the head. Since the shock wave propagates from different directions and heights, the protective effect of the helmet on the face is minimal. This study can provide important references for biomechanical research of human head injury under continuous frontal blast shock wave and the design of new helmets.