The invention discloses an SOC estimating method for a power battery of an unmanned aerial vehicle. The method specifically comprises the steps of SOC estimating in a low temperature state and SOC estimating in a power-on state. Whether power is enough for taking off is determined at the moment of taking off. The battery remaining capacity is estimated in real time according to the temperature of the unmanned aerial vehicle which takes off. Whether the unmanned aerial vehicle can return safely is determined. SOC estimation of the power battery of the unmanned aerial vehicle in long-term placement and at low temperature of high altitude flight is realized. The estimation accuracy is improved. The problem of overcharge or overdischarge during the use of the battery is avoided. Levitation height alerts of the unmanned aerial vehicle are provided through real-time estimation. The navigation safety of the unmanned aerial vehicle is improved.