An independently driven and steered four-wheel platform for detecting phenotype of field crop was designed to stably and effectively obtain phenotype information of field crop with high flexibility. It mainly consists of the walking system,the control system and the acquisition system of phenotype information. Creo software is used to design the structure of the platform and perform finite element simulation analysis under different working conditions of the main frame. A control system is developed with Siemens 1200 series PLC as the main controller to realize the platform’s in-situ steering,lateral movement and Ackerman steering mode control. The four-wheel coordinated control method based on fuzzy PID was used to realize the synchronous movement of four-wheel. This platform can load RGB cameras,thermal infrared cameras,hyperspectral cameras and other sensors for phenotypic information collection according to the requirements of detection,and form a mobile darkroom during the collection process,effectively reduce the impact of the external environment on the effect of collecting phenotypic information. The results of field test showed that a single uninterrupted operation was up to 6 hours under full power. The results of four-wheel coordinated motion test showed that the maximum deviation rate of the wheel speed was 1%,and the average deviation rate of the platform driving straight on cement ground and in the field was 2.14 % and 2.57%,with good mobile stability. When RGB and thermal infrared cameras were loaded for the acquisition of crop phenotypic information,120 breeding plots in field were detected per hour. The RGB images of cotton under the non-dark room environment and the dark room environment in different time periods were collected separately and the leaf area was extracted. The results showed that the RGB images collected by the platform were more stable and reliable. The results of collecting and analyzing RGB images,thermal infrared and hyperspectral images under the dark room environment showed that the images collected by the platform had good quality and effective information.