Imaging spectrometer can acquire spatial and spectral information of the target at the same time, achieve high-precision, non-destructive, non-contamination and large area instantaneous inspection of the fruit. In order to get the imaging spectrum of the fruit, compact imaging spectrometer with convex grating produced by self was designed, it has the advantages of good performance, small volume and low weight, its resolution at 578 nm is 2.1 nm, and spectral line bend and chromatic distortion are both smaller than 0.6%. Laboratory test of the imaging spectrometer and the experiment of getting the imaging spectrum of apple were done, and the result shows that the imaging spectrometer satisfies the design requirement and can acquire the imaging spectrum of apple rapidly with high precision for inspection of fruit quality.