As the most essential pigment included in green plants, chlorophyll content is an important indicator in monitoring the growth of plants. The traditional spectrophotometric method used to measure the chlorophyll content of plant leaves has the advantages of high measurement accuracy and good repeatability, but the measurement process are timeconsuming. Therefore, developing a portable rapid chlorophyll detector with simple operation and low cost, and could be used insitu measurement will be appreciated by agricultural and forestry practitioners. Since the absorption peaks of chlorophyll a and b appeared at 660nm and 460nm, a portable chlorophyll content detector was developed based on this phenomenon. The hardware of the detector consisted of a single chip microcomputer, light sources module, light sensors, power module, and input and output module. The software, developed by using Keil C51 language, including main function and several subfunctions to detect the light, process data, calculate the chlorophyll content and display the values on screen. The leaves of spinach, big green vegetables and lettuce were used as samples, and the relationship between their chlorophyll contents and light absorbance at 460nm and 660nm were studied. It was found that the absorbance was increased with the increase of chlorophyll content, and their relationship could be described by first degree in two variable equation with the coefficient of determination of 080. The validation experiment on the developed detector showed that contrasted with the spectrophotometer method, the absolute measurement error of the developed detector was within the range of -0.32~0.20mg/g, and its mean absolute error was 0.14mg/g. Contrasted with the measured SPAD values by using SPAD-502 chlorophyll meter, the measurement error of the SPAD values measured by the developed detector was within the range of -3.3~1.8, and its mean absolute error was 1.1. Moreover, the measurement time of the detector was less than 2s and the cost of the detector was not high.