Chlorophyll content is one of the most important parameters for monitoring the crop growth status.Lack of chlorophyll can affect the growth status and the nutrient levels.This can also change the spectral reflectance characteristics of crops.Thus, it is reasonable to measure the chlorophyll content with multi-spectral image processing.In the field production, it is easy to install the multi-spectral camera on the vehicle or agricultural equipment.The data could be measured real-timely when the vehicle moving.Real time acquisition of the information about sampling position and the way to control spectral camera are the basis of farmland auxiliary management and the support of scientific production decision-making.In order to monitor the crop growth status in the field non-destructively, a multi-spectral image acquisition device was developed.A multi-spectral 2-channel CCD sensor was used.It was designed based on the principle of splitter prism with two reflecting mirror.The reflectance of crop canopy was measured and split into two bands with 400-700nm and 760-1000nm.The multispectral image was output as RGB (red, green, blue) and NIR images with the center length at 470nm, 550nm, 620nm and 800nm separately.The position monitoring and camera control system was developed, it was used to acquire the sampling position and trigger the camera.The developed software was installed in a panel computer.It was developed based on VC++ in the environment of Windows with three basic capabilities including parameter setting, data displaying and storage, and acquisition controlling.The parameter setting function included the image parameters, serial port parameters and plot boundary.The serial port parameters were the port number, baud rate and parity bit.The GPS data could be read from the serial port after parameters set correctly.The plot boundary included name,location, area, plants of plot, and longitude and latitude of four boundary points.Among them, the longitude and latitude of four boundary points were used to draw the plot boundary map.The GPS information contained UTC date, UTC time, current longitude, current latitude, ground heading,altitude and ground speed.Using the current longitude and latitude, the current location could be marked with a little square on the plot boundary map.When the data was located in the setting region, the multi-spectral camera was triggered.Then the sampling position could be tracked.The system was used in the field experiment, the canopy images of crop were collected and processed.image parameters were calculated such as Normalized Difference Vegetation Index (NDVI),Normalized Difference Green Index (NDGI), Ratio Vegetation Index (RVI) and Difference Vegetation Index (DVI) based on the average gray value of R, G and NIR.The distribution of them could figured.It provides a feasible method to measure crop grow information efficiently.