This paper analyzes the theoretical basis of the relevant papers. First, the meaning and connotation of corporate bond yield spreads to define the difference between corporate bonds and corporate bonds; secondly, analyzed the determinants of corporate bond yield spreads, including: macroeconomic factors, capital market factors, individual factors of corporate bonds; and then introduces research methods of corporate bond yield spreads, including GARCH and ARCH methods, time series analysis, panel data fixed effects model, state space model and Kalman filter method.