Impurity spectra have been measured to evaluate impurity behavior and plasma parameter in the tandem mirror GAMMA 10. An ultraviolet and visible (UV/visible) spectroscopic system has been designed to measure the impurity emission intensity in detail. It consists of two spectrometers to obtain an entire wavelength range of UV/visible impurity spectra in one plasma shot. The time-varying emission intensity of radiation spectra have been measured successfully with electron cyclotron resonance heating (ECRH) or pellet injection plasmas. We evaluate radiation loss with ECRH from the GAMMA 10 plasma in the UV/visible range; further we estimate the electron density and temperature after applying the spectral intensity data measured from the pellet injection experiment to a collisional-radiative model.