The path planning method is one of the main research directions in current UAV(unmanned aerial vehicle) technologies.
In this paper we perform analyses on the adversarial environment which may be broken through during the UAV mission
for ground observation, and carry out the grade classification according to the threat level. On the basis of genetic
algorithm, the encoding method of dimension reduction and direct quantization is used to combine the threat value of
each leg with the flight distance, so as to construct the fitness evaluation function based on the threat amount and design
the algorithm. This method is proven to be able to converge effectively and quickly via the simulation experiments,
which meet the threat restriction and applicability of UAV in route planning.