Non-destructive testing, as a new, rapid, non-destructive technology, is the direction of agricultural produce testing in the future. In this study, the nitrogen content of cucumber leaves was predetermined using near infrared spectroscopy technology. The main results were as follows: The authors measured the nitrogen content in cucumber leaves with Kjeldahl method and near infrared spectroscopy, then established a model between them, and processed a external verification next. The verification results showed that the determination coefficient of the model was 0.406　6, relative standard deviation is 0.155　9, and calibration standard deviation is 0.72； Then the authors predicted the cucumber leaves nitrogen content with this model, and the results showed that the mean absolute percent error was 0.59, average relative error was 13.88, and correlation coefficient of the chemical values and predicted values was 0.637　7. So it was proved that this model had a certain feasibility in vegetable leaves nitrogen testing.