An open circuit detection method and an LED display device are provided, relating to the technical field of LED display, wherein the open circuit detection method includes: supplying an open-circuit detection voltage to any row line to be detected among a plurality of row lines in the LED display device, and pulling down electric potentials of row lines other than the row line to be detected among the plurality of row lines to a first preset value, wherein the first preset value is smaller than an ON-voltage of each of the LED lamp beads and greater than 0; detecting whether the respective column lines include a column line having an electric potential lower than a second preset value, wherein if yes, it is determined that the LED display device has an LED lamp bead in an open circuit state.