With the development of unmanned aerial vehicle (UAV) platforms and multispectral sensors, the application of multispectral remote sensing in light and small UAVs is becoming more and more extensive. Unmanned aerial vehicle remote sensing platforms equipped with different sensors have recently become an important approach for fast and non-destructive data acquisition and have the advantage of flexible and convenient operation, on-demand access to data and high spatial resolution. It has shown great potential in the fields of agriculture, forestry, ecology, environmental protection and so on. Firstly, this paper summarizes the main flight platform and the multispectral camera hardware technology. Secondly, the geometric and radiometric calibration of UAV multispectral image data processing technology are summarized. Thirdly, UAV multispectral remote sensing applications are systematically analyzed and summarized. Finally, some existing problems of the current UAV multispectral remote sensing system and the direction of development are proposed, in order to provide a reference to the related research. With the continuous progress of UAV based multispectral hardware technology, combined with the increasingly mature image processing and analysis software, the accuracy and ease of use of UAV multispectral remote sensing system will be improved. We suggest that practitioners from all sectors of the industry work closely with experts in remote sensing and computer science to develop and popularize multispectral remote sensing technology for unmanned aerial vehicles.