NbSiN films are deposited on glass substrates with radio frequency (RF) magnetron sputtering method by taking Nb and Si as targets. The effects of powers of silicon target and niobium target, flow rate of nitrogen and sputtering time on optical properties of films are studied, and the optimal preparation process paremeters are obtained. The test results show that the films are uniformly and compactly deposited under the optimal process paremeters, which mainly compose of NbN, NbSiN, amorphous Si3N4, and little SiO2 and Nb2N2-xO3+x. The optical property analysis shows that the visible light transmissivity of NbSiN films is 90.5% at 550 nm (the most sensitive wavelength for human eyes) and the infrared reflectivity is about 28%, which indicates that the optical property is excellent.