The tradition spectrometer based on the grating to reconstruct the wavelength. The structure of the grating will influence the resolution of the spectrometer. The high-resolution spectrometer usually has high requirement for the grating. While the grating structure is limited to the fabrication method. Thus, the cost of the high-resolution spectrometer is always high. Besides the grating, the size of the spectrometer can also affect the resolution of the spectrometer. Hence, the high-resolution spectrometer is always large. To overcome these disadvantages, the speckle-based spectrometer has been currently studied by many scholars. Through using multimode fiber[1-3], the speckle patterns can be generated. Then, the reconstruction algorithms are applied to reconstruct the wavelength. In order to find a way to build a portable and low-cost spectrometer based on mobile phone, a spectrometer device based on speckle reconstruction is put forward in this article. The frosted glass is used as the speckle generate medium and the mobile phone is adopted to capture the pictures of the speckle. Through applying the minimum energy algorithm, this device is able to reconstruct certain wavelength.Master of Science (Biomedical Engineering