In order to improve the quality of greenhouse vegetable plug seedlings and realize rapid detection of growth information of greenhouse vegetable plug seedlings, a device for detecting the growth information was designed. The detection device contained a weighing unit, an image acquisition unit, a light source unit and a control processing unit, mainly realizing vegetable seedling morphological index of projection area, stem diameter and plant height detection and weight information collection. The light source unit was composed of high-power LEDs. The image acquisition unit was made up of two cameras, the first camera in the vertical downward orientation, was used to obtain projection area parameter of vegetable seedling, the second camera in the horizontal position, was employed to capture of vegetable seedling stem diameter and plant height parameters. The weighing unit adopted a high precision weight sensor to obtain the weight information of the vegetable seedlings. The control processing unit included a single chip microcomputer and a computer. The single chip microcomputer was introduced to control the background board opening and closing, and to control camera work. The computer was mainly used to process images and realize information fusion and the design of humancomputer interaction interface. The software system of the device was developed based on C++ language, including image processing algorithm and control programs. The detection error of the device was less than 5% for morphological indicators and weight information. The results showed that the greenhouse vegetable seedling growth information detection device had high detection accuracy.