An air conditioner heating mode control method includes: Step 11: obtaining an indoor temperature and comparing the indoor temperature with a first indoor temperature threshold as an air conditioner running at the heating mode; Step 12: performing a dual PID control process if the indoor temperature is less than or equal to the first indoor temperature threshold; wherein the dual PID control process including: calculating the difference between the indoor temperature and a set indoor target temperature to obtain a indoor temperature difference; performing a PID calculation according to the indoor temperature difference to obtain a first target frequency; obtaining a coil temperature of an indoor unit heat exchanger; calculating the temperature difference between the coil temperature and a coil target temperature to obtain a coil temperature difference; performing a PID calculation according to the coil temperature difference to obtain a second target frequency; comparing the first target frequency with the second target frequency; and performing a frequency control on the compressor in which the greater one between the first target frequency and the second target frequency is used as the target frequency; wherein the coil target temperature is determined according to the indoor temperature. The present invention also discloses an air conditioner heating mode control device.