Objective:To ensure the course of the supratrochlear artery by studying the anatomy to provide anatomic basis for the design of the modified paramedian forehead flap. Methods:Seven cadavers(twelve supratrochlear arteries) were used in the study. The initial position, the course of the supratrochlear artery(supraorbital rim and midline as landmark) and the communication between the supratrochlear artery and other arteries were recorded. Results:The supratrochlear artery exited the foramen supratrochlear which was(1.33 ± 0.14) cm away from the midline and ascended inward. It had an angulus(about 82 degree) towards the supraorbital rim level. The course of the supratrochlear artery was divided into three parts:part I,the artery was located between the corrugator and orbicularis oculi muscles;partⅡ,close to the previous one,the artery piercing the frontalis muscle approximately at the supraorbital rim level and ascended on the surface of the frontalis muscle from the supraorbital rim level to the place(0.93 ± 0.23)cm above it;and part Ⅲ,it ascended continuely within the subcutaneous plane and then intracutaneous plane. The branch of the supratrochlear artery was found at the level(1.26±0.20)cm above the supraorbital rim in five cadavers(eight supratrochlear arteries). And it ascended outward within the subcutaneous plane. The supratrochlear artery communicated with the branch of the supraorbital artery and the frontal branch of the superficial temporal artery. The forehead arterial anastomotic plexus was organized by those arteries. No muscular branches was found in the frontalis muscle. Bilateral supratrochlear arteries communicated with each other. Conclusion:The supratrochlear artery travels superficial to the frontalis muscle after it reaches the supraorbital rim. So we can design the paramedian forehead flap by the course of the vessel, and the flap can be elevated without muscle,except for the pedicled part.