Thermal convection based accelerometers and heating control methods therefor are described. The heating control method includes: sensing a temperature in the enclosed cavity and generating a temperature voltage signal; amplifying the temperature voltage signal to obtain an amplified temperature voltage signal; calculating a voltage difference between the amplified temperature voltage signal and a reference voltage signal; converting the voltage difference into a digital sequence by using a modulator; obtaining a heating power adjustment factor representing the voltage difference based on the digital sequence; obtaining a heating power control parameter based on the heating power adjustment factor and an initial heating power factor; converting the heating power control parameter into a switch control signal; and turning on or off a heating control switch coupling with a heating resistor for heating the enclosed cavity in series according to the switch control signal.