Carbon-based electric heating ink was prepared and closely connected with metal strips by screen printing to prepare flexible electric heating devices. Under different working voltages, the flexible electric heating device heats uniformly and stably; the greater the energizing voltage of the flexible electric heating device, the higher its saturation temperature; the smaller the area of the flexible electric heating device, the higher its saturation temperature. After the flexible electric heating device was folded and bent nearly 2000 times, its resistance change rate was less than 4%. Comprehensive test results show that the flexible electric heating device has good electric heating performance and excellent mechanical properties.