The invention relates to a flight path planning method for coordinated detection and obstacle avoidance of an unmanned aerial vehicle group. The method includes the following steps: S1. setting an unmanned aerial vehicle group flying area and designating a task monitoring area in the flying area; S2. defining yaw angle independent variables of N unmanned aerial vehicles, and initializing yaw angles, location coordinate information in the flying area, the number of current searching steps k=0, and the cumulative coverage percent=p1 on the task area at the current moment of the N unmanned aerialvehicles; S3. predicting flight path yaw angles and location information of (k+1) steps of the N unmanned aerial vehicles in the flying area, and separately calculating a coverage area and a fitnessfunction value; S4. comparing all possible fitness values, selecting a yaw angle and location information of an optimal fitness value as information of the (k+1)th step, and storing the yaw angle andthe location information in a flight path chart; and S5. enabling k=k+1, judging whether k=1 or percent=1, if yes, ending the planning, and otherwise, continuing S3 to S5. The method of the inventioncan realize the maximum monitoring coverage area, avoid obstacles and a required flight path has no fixed starting point and ending point.