Northern corn leaf blight (NCLB) occurs in major maize-producing regions globally, leading to a reduction in both maize quality and yield. Disease identification typically occurs when lesions are more obvious, making it challenging to prevent and control the disease promptly. This study proposes a one-dimensional convolutional neural network (1DCNN) model for early disease detection using hyperspectral imaging. In this research, NCLB was selected as the target disease. After manual inoculation, maize leaves at the silking stage were used for experiments, when lesions had just begun to appear, but the disease could not yet be visually identified. First, hyperspectral images were captured using the SOC710E spectrometer, and spectral data of both healthy and NCLB-infected maize leaves were obtained by selecting regions of interest. Four spectral preprocessing methods Savitzky-Golay smoothing (SG), multiplicative scatter correction (MSC), standard normal variate transformation (SNV), and detrending (DT) were applied to remove noise from the spectral data. Supervised learning algorithms, random forest (RF) and K-nearest neighbors (KNN), were employed for hyperspectral image classification, with accuracy as the evaluation metric. The results indicated that MSC was the optimal preprocessing method, achieving prediction accuracies of 88.13% and 86.26% for the RF and KNN models, respectively. Next, a competitive adaptive reweighted sampling (CARS) algorithm was applied to extract characteristic wavenumbers from the maize leaf spectral data, reducing the original 260 wavenumbers to 48 selected features. Finally, a 1DCNN deep learning model was developed for classification, achieving an accuracy of 99.61%. Compared with traditional classification models such as KNN, RF, partial least squares discriminant analysis (PLS-DA), backpropagation neural network (BP), and support vector machines (SVM), the proposed model improved recognition accuracy by 5.94%, 6.88%, 6.48%, 8.27%, 12.12%, respectively. These findings demonstrate that combining hyperspectral technology with deep learning models provides a new approach and method for early detection of maize diseases, enhancing the accuracy and timeliness of disease recognition.