For Directional Sensor Network (DSN) consists of sensors with adjustable directions, in order to reduce coverage holes and overlapping area to the utmost, so as to improve the effective coverage, a differential evolution-mixed virtual force based coverage algorithm was put forward. Firstly, the directional sensing model was established, the mixed virtual forces between nodes, nodes and obstacles, nodes and the boundary were analyzed, and the adjustment formula between node rotation angle and force was established. Secondly, the differential evolution model was used to weaken defects of local suboptimal solutions caused by mixed virtual force. The virtual force was taken as a factor of evolutionary update. The best fitness value was found between nodes to optimize the effective coverage through mutation, crossover and selection operations. The coverage simulation experiments show that, in the detection area of 100 m×100 m, after 100 times of random deployment, the average effective coverage rate of the network is increased by 19.68% by the differential evolution-mixed virtual force algorithm, and the average effective coverage rate of the network is respectively increased by 10.32% and 11.35% by mixed virtual force algorithm and differential evolution algorithm. The network of differential evolution-mixed virtual force algorithm tends to be stable after 80 iterations, while the network of mixed virtual force algorithm and differential evolution algorithm respectively requires 130 iterations and 140 iterations. Compared with mixed virtual force algorithm and differential evolution algorithm, the differential evolution-mixed virtual force based coverage algorithm is faster, and can improve the effective coverage rate more obviously.