A parameter determination method for a spread spectrum circuit, a clock spread spectrum method, a parameter determination device for a spread spectrum circuit, and a clock spread spectrum device are disclosed. The parameter determination method for the spread spectrum circuit includes: obtaining a base time unit and a target frequency; determining a spread spectrum depth coefficient according to the base time unit and the target frequency; determining whether the spread spectrum depth coefficient is greater than or equal to a base spread spectrum depth coefficient; if yes, determining the spread spectrum depth coefficient as a standard spread spectrum depth coefficient and determining a standard frequency control word according to the standard spread spectrum depth coefficient; and if no, adjusting the base time unit until a corresponding spread spectrum depth coefficient corresponding to the base time unit is greater than or equal to the base spread spectrum depth coefficient.