Five new furanocoumarins, dahuribirin H (<b>1</b>), dahuribirin I (<b>2</b>), (2'<i>S</i>)-(+)-5-(2'-hydroxy-3'-methylbut-3'-enyloxy)-8-(3''-methylbut-2″-enyloxy)psoralen (<b>3</b>), (2'<i>R</i>)-(+)-5-(2',3'-epoxy-3'-methylbutoxy)-8-(3″-methylbut-2″-enyloxy)psoralen (<b>4</b>), and 5-methoxy-8-((<i>Z</i>)-4'-(3″-methylbutanoate)-3'-methylbut-2'-enyloxy)psoralen (<b>5</b>), along with 15 known compounds (<b>6</b>-<b>20</b>), were isolated from the roots of <i>Angelica dahurica</i>. The structures of the new compounds were elucidated by spectroscopic analysis, along with electronic circular dichroism calculations and Mosher ester analysis. Compounds <b>3</b>, <b>4</b>, <b>11</b>, <b>13</b>, and <b>16</b> reduced H<sub>2</sub>O<sub>2</sub>-induced cell death in HepG2 cells and attenuated reactive oxygen species (ROS) formation without showing cytotoxicity, suggesting that these compounds might have cytoprotective effects against H<sub>2</sub>O<sub>2</sub>-induced oxidative damage via ROS scavenging activities.