The embodiment of the present invention discloses a loop compensation circuit and a switching power supply circuit. The loop compensation circuit can comprise: a voltage detection circuit, a control chip and a RC circuit, and the voltage detection circuit is coupled to a voltage generation circuit, and employed to detect a variation of an output voltage of the voltage generation circuit; the control chip is respectively coupled to the voltage detection circuit and the RC circuit, and employed to detect a response speed of the loop compensation circuit and to adjust a parameter of the RC circuit according to the response speed of the loop compensation circuit and the variation of the output voltage of the voltage generation circuit for adjusting the response speed of the loop compensation circuit.