The Visible and Near-Infrared Imaging Spectrometer (VNIS) onboard China's Chang'E 3 lunar rover is capable of simultaneously in situ acquiring full reflectance spectra for objects on the lunar surface and performing calibrations. VNIS uses non-collinear acousto-optic tunable filters and consists of a VIS/NIR imaging spectrometer (0.45-0.95 μm), a shortwave IR spectrometer (0.9-2.4 μm), and a calibration unit with dust-proofing functionality. To been underwent a full program of pre-flight ground tests, calibrations, and environmental simulation tests, VNIS entered into orbit around the Moon on 6 December 2013 and landed on 14 December 2013 following Change'E 3. The first operations of VNIS were conducted on 23 December 2013, and include several explorations and calibrations to obtain several spectral images and spectral reflectance curves of the lunar soil in the Imbrium region. These measurements include the first in situ spectral imaging detections on the lunar surface. This paper describes the VNIS characteristics, lab calibration, in situ measurements and calibration on lunar surface.